Explore · MATH-5B-C11-L09-OPEN
Construct a rectangle 7 cm long and 6 cm wide; identify four right angles.
Great Inheritance Mathematics Term B · Original independent course
Drawing Triangles and Quadrilaterals
Watch for: Sketching without measuring or drawing impossible triangles.. Explain what the quantities mean before calculating.
Opening task
Prerequisite check
Before instruction · MATH-5B-C11-L09-PREREQ
Which instrument measures angles in degrees?
Show worked answer (after attempting)
Answer: Protractor
A protractor has degree scales aligned with a starting ray.
Understand the idea
Construct specified plane shapes using ruler and protractor, and verify Course and angle constraints. The essential earlier idea is: Protractor skills, triangle inequality and parallel lines.. The model below will always use the actual quantities from the worked problem. Check sketching without measuring or drawing impossible triangles when you explain your answer.
Three worked examples
Worked example 1 · MATH-5B-C11-L09-Q01
Construct a rectangle 6 cm long and 5 cm wide; identify four right angles.
Solution: Rectangle with 4 right angles and correct side lengths
Use a ruler and protractor; draw 6 cm, construct 90° at both ends, measure 5 cm, join the top edge.
Worked example 2 · MATH-5B-C11-L09-Q02
Draw a triangle with base 7 cm and base angles of 50° and 60°.
Solution: Triangle with third angle 70° and given base/angles
Draw the 7-cm base; draw 50° and 60° rays from its endpoints to meet. The third angle is 70°.
Worked example 3 · MATH-5B-C11-L09-Q03
Construct a parallelogram with adjacent sides 8 cm and 7 cm and one interior angle 60°.
Solution: Parallelogram with opposite sides parallel and length/angle constraints
Draw one 8-cm side; construct a 60° ray and mark 7 cm; complete opposite parallel sides.
Check understanding
1 · MATH-5B-C11-L09-Q04
Construct a rectangle 7 cm long and 6 cm wide; identify four right angles.
Show worked answer (after attempting)
Answer: Rectangle with 4 right angles and correct side lengths
Use a ruler and protractor; draw 7 cm, construct 90° at both ends, measure 6 cm, join the top edge.
2 · MATH-5B-C11-L09-Q05
Draw a triangle with base 8 cm and base angles of 51° and 59°.
Show worked answer (after attempting)
Answer: Triangle with third angle 70° and given base/angles
Draw the 8-cm base; draw 51° and 59° rays from its endpoints to meet. The third angle is 70°.
3 · MATH-5B-C11-L09-Q06
Construct a parallelogram with adjacent sides 9 cm and 8 cm and one interior angle 61°.
Show worked answer (after attempting)
Answer: Parallelogram with opposite sides parallel and length/angle constraints
Draw one 9-cm side; construct a 61° ray and mark 8 cm; complete opposite parallel sides.
Guided practice
1 · MATH-5B-C11-L09-Q07
Construct a rectangle 8 cm long and 7 cm wide; identify four right angles.
Show worked answer (after attempting)
Answer: Rectangle with 4 right angles and correct side lengths
Use a ruler and protractor; draw 8 cm, construct 90° at both ends, measure 7 cm, join the top edge.
2 · MATH-5B-C11-L09-Q08
Draw a triangle with base 9 cm and base angles of 52° and 58°.
Show worked answer (after attempting)
Answer: Triangle with third angle 70° and given base/angles
Draw the 9-cm base; draw 52° and 58° rays from its endpoints to meet. The third angle is 70°.
3 · MATH-5B-C11-L09-Q09
Construct a parallelogram with adjacent sides 10 cm and 9 cm and one interior angle 62°.
Show worked answer (after attempting)
Answer: Parallelogram with opposite sides parallel and length/angle constraints
Draw one 10-cm side; construct a 62° ray and mark 9 cm; complete opposite parallel sides.
4 · MATH-5B-C11-L09-Q10
Construct a rectangle 9 cm long and 8 cm wide; identify four right angles.
Show worked answer (after attempting)
Answer: Rectangle with 4 right angles and correct side lengths
Use a ruler and protractor; draw 9 cm, construct 90° at both ends, measure 8 cm, join the top edge.
Independent practice
1 · MATH-5B-C11-L09-Q11
Draw a triangle with base 10 cm and base angles of 53° and 57°.
Show worked answer (after attempting)
Answer: Triangle with third angle 70° and given base/angles
Draw the 10-cm base; draw 53° and 57° rays from its endpoints to meet. The third angle is 70°.
2 · MATH-5B-C11-L09-Q12
Construct a parallelogram with adjacent sides 11 cm and 10 cm and one interior angle 63°.
Show worked answer (after attempting)
Answer: Parallelogram with opposite sides parallel and length/angle constraints
Draw one 11-cm side; construct a 63° ray and mark 10 cm; complete opposite parallel sides.
3 · MATH-5B-C11-L09-Q13
Construct a rectangle 10 cm long and 9 cm wide; identify four right angles.
Show worked answer (after attempting)
Answer: Rectangle with 4 right angles and correct side lengths
Use a ruler and protractor; draw 10 cm, construct 90° at both ends, measure 9 cm, join the top edge.
4 · MATH-5B-C11-L09-Q14
Draw a triangle with base 11 cm and base angles of 54° and 56°.
Show worked answer (after attempting)
Answer: Triangle with third angle 70° and given base/angles
Draw the 11-cm base; draw 54° and 56° rays from its endpoints to meet. The third angle is 70°.
5 · MATH-5B-C11-L09-Q15
Construct a parallelogram with adjacent sides 12 cm and 11 cm and one interior angle 64°.
Show worked answer (after attempting)
Answer: Parallelogram with opposite sides parallel and length/angle constraints
Draw one 12-cm side; construct a 64° ray and mark 11 cm; complete opposite parallel sides.
6 · MATH-5B-C11-L09-Q16
Construct a rectangle 11 cm long and 10 cm wide; identify four right angles.
Show worked answer (after attempting)
Answer: Rectangle with 4 right angles and correct side lengths
Use a ruler and protractor; draw 11 cm, construct 90° at both ends, measure 10 cm, join the top edge.
7 · MATH-5B-C11-L09-Q17
Draw a triangle with base 12 cm and base angles of 55° and 55°.
Show worked answer (after attempting)
Answer: Triangle with third angle 70° and given base/angles
Draw the 12-cm base; draw 55° and 55° rays from its endpoints to meet. The third angle is 70°.
8 · MATH-5B-C11-L09-Q18
Construct a parallelogram with adjacent sides 13 cm and 12 cm and one interior angle 65°.
Show worked answer (after attempting)
Answer: Parallelogram with opposite sides parallel and length/angle constraints
Draw one 13-cm side; construct a 65° ray and mark 12 cm; complete opposite parallel sides.
Challenge and error analysis
1 · MATH-5B-C11-L09-ERR1
The assigned question is: “Draw a triangle with base 15 cm and base angles of 58° and 52°.” A learner wrote: “I constructed the shape using the stated length 15 but did not enforce the named angle or parallel-side condition; my construction meets the answer Triangle with third angle 70.1° and given base/angles.” Identify a concrete invalid step or assumption. Work out the correct result and explain why it is valid.
Show worked answer (after attempting)
Answer: Correct result: Triangle with third angle 70° and given base/angles
The attempted reasoning or reported result does not satisfy the specified operation, units or geometric conditions. Correct mathematical result: Triangle with third angle 70° and given base/angles. Recompute from the given data: Draw the 15-cm base; draw 58° and 52° rays from its endpoints to meet. The third angle is 70°.
2 · MATH-5B-C11-L09-ERR2
The assigned question is: “Construct a parallelogram with adjacent sides 16 cm and 15 cm and one interior angle 68°.” A learner wrote: “I constructed the shape using the stated length 16 but did not enforce the named angle or parallel-side condition; my construction meets the answer It cannot be determined from this information..” Identify a concrete invalid step or assumption. Work out the correct result and explain why it is valid.
Show worked answer (after attempting)
Answer: Correct result: Parallelogram with opposite sides parallel and length/angle constraints
The attempted reasoning or reported result does not satisfy the specified operation, units or geometric conditions. Correct mathematical result: Parallelogram with opposite sides parallel and length/angle constraints. Recompute from the given data: Draw one 16-cm side; construct a 68° ray and mark 15 cm; complete opposite parallel sides.
Exit check
Exit · MATH-5B-C11-L09-Q19
Construct a rectangle 12 cm long and 11 cm wide; identify four right angles.
Show worked answer (after attempting)
Answer: Rectangle with 4 right angles and correct side lengths
Use a ruler and protractor; draw 12 cm, construct 90° at both ends, measure 11 cm, join the top edge.