Area of a triangle (½ab sin C)
Edexcel GCSE Maths revision on Area of a triangle (½ab sin C). Aligned to the Pearson Edexcel GCSE Mathematics 1MA1 specification. This bank has 16 practice questions on this topic.
Sample questions (3 of 16)
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Question 1
What is the area of a triangle with two sides of 6 cm and 8 cm and an included angle of 30 degrees?
- A) 12 square cm as the area is half product of sides and sine
- B) 24 square cm as the area is product of sides and sine
- C) 48 square cm as the area is product of sides by cosine
- D) 18 square cm as the area is sum of sides times sine
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Answer: 12 square cm as the area is half product of sides and sine
The formula is 0.5 * a * b * sin(C). Calculating 0.5 * 6 * 8 * sin(30) gives 0.5 * 48 * 0.5, which equals 12 square cm. Students often forget to multiply by 0.5, leading to the distractor of 24.
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Question 2
What is the area of a triangle with sides of 10 cm and 12 cm and an included angle of 90 degrees?
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Answer: 60
Since sin(90) is 1, the formula simplifies to 0.5 * base * height. Calculating 0.5 * 10 * 12 results in 60 square cm.
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Question 3
Which expression correctly calculates the area of a triangle with sides x and y and included angle Z?
- A) 0.5 times x times y times sin(Z)
- B) 0.5 times x times y times cos(Z)
- C) x times y times sin(Z) divided 2
- D) x times y times cos(Z) divided 2
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Answer: 0.5 times x times y times sin(Z)
The correct formula is 0.5 * a * b * sin(C). While 'x times y times sin(Z) divided 2' is mathematically equivalent, the standard algebraic representation is 0.5 * x * y * sin(Z).
Want to test yourself on the remaining cards for this topic?
13 more questions on Area of a triangle (½ab sin C) — plus mistakes tracking and spaced repetition across the whole Maths spec.