Area of a triangle using ½ab sin C

Sample Area of a triangle using ½ab sin C questions

A few of the 14 questions, from easier to harder. Choose your exam board and tier to practise them, with every answer marked.

1. Question 12 marksGrade 6-7
   In triangle ABC, side a = 10.9 cm and side b = 4 cm are the two sides that meet at angle C, and angle C = 94°. Work out the area of the triangle. Give your answer correct to 1 decimal place.
   Show the worked solution

   $\text{Area} = \dfrac{1}{2}ab\sin C$

What are the common mistakes in Area of a triangle using ½ab sin C?

When a pupil makes one of these on Revision Workshop, the marking engine names the mistake and explains it, instead of just marking the answer wrong.

• Uses cosine where sine was the correct trig ratio for the given sides/angle

  Used $\cos C$ instead of $\sin C$ in the area formula - the area formula uses the SINE of the included angle, not the cosine (the cosine rule is a different formula, for finding sides/angles, not area)

• Omits the factor of a half from a formula (e.g. area of a triangle)

  Calculated $ab\sin C$ but forgot to multiply by

Quick answers about Area of a triangle using ½ab sin C

How many Area of a triangle using ½ab sin C practice questions are there?

There are 14 self-marking GCSE and IGCSE Maths questions on Area of a triangle using ½ab sin C, written for AQA, Pearson, OCR, Pearson International GCSE Maths A (4MA1), Cambridge IGCSE Mathematics (0580), Cambridge IGCSE (9-1) Mathematics (0980) across Higher and Extended tier. Each one is marked instantly and has a full worked solution.

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