Non-right-angled: Challenge & Extension

Mathematics
Grade 7
12 questions
~24 mins
1 views0 downloads

About This Worksheet

A worksheet exploring the area of non-right-angled triangles using the formula ½abSinC, including practice, problem solving, real-world applications, and extension challenges.

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Full preview • 12 questions

Non-right-angled: Challenge & Extension

Subject: MathematicsGrade: Grade 7
Name:
Date:
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Untitled Worksheet

Grade Grade 7
A

Practice Questions

Answer all questions. Show your working in the grid spaces provided.
1.
Calculate the area of a triangle with sides a = 8 cm, b = 6 cm, and the included angle C = 60°.
[3 marks]
2.
Given sides a = 10 cm, b = 7 cm, and angle C = 45°, find the area of the triangle.
[3 marks]
3.
A triangle has sides a = 5 cm, b = 9 cm, and angle C = 120°. Calculate its area.
[3 marks]
4.
Construct a triangle with sides a = 7 cm, b = 9 cm, and angle C = 80°. Use the grid to depict the triangle.
[2 marks]
5.
Plot the graph of y=2x and identify a point where a triangle with sides a=5, b=12 and angle C=60° can be constructed.
[2 marks]
B

Problem Solving & Reasoning

Solve these multi-step problems. Show detailed working.
1.
A triangle has sides a = 8 cm, b = 10 cm, and included angle C = 75°. Calculate its area and explain each step.
[4 marks]
2.
Two sides of a triangle are 6 cm and 9 cm, with an included angle of 100°. Find the area, then determine if this shape can be a potential triangle with the given measurements.
[4 marks]
C

Real-world Applications

Interpret the problem and calculate the required area.
1.
A park has two paths that form a triangle with sides 50 m and 70 m, and the included angle is 40°. Find the area of the park section enclosed by the paths.
[3 marks]
D

Challenge & Extension

Attempt these advanced problems to deepen your understanding.
1.
Given a triangle with sides a=9 cm, b=12 cm, and area = 54 cm², find the measure of angle C using the Law of Sines and the area formula.
[3 marks]
2.
A triangle has sides a=13 cm, b=14 cm, and area = 84 cm². Use the formula ½abSinC to find angle C, and verify your result with the Law of Cosines.
[4 marks]
E

Mixed Review & Error Analysis

Identify the errors in the following student solutions and correct them.
1.
A student calculates the area with sides a=8 cm, b=5 cm, and angle C=90°, using the formula ½abSinC. Is this correct? If not, explain and correct the mistake.
[2 marks]
2.
A solution shows using sides a=7, b=9, and angle C=60°, but mistakenly uses sin60° = 0.6 instead of 0.866. Identify and correct the mistake.
[2 marks]

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Details

Created
1/1/2026
Updated
1/1/2026
Type
worksheet