Home   >  Worksheets   >  GCSE questions by topic   >  Area of any triangle

Area of any triangle

Free Printable Area of any triangle PDF Worksheets, Revision Guide & GCSE Past Paper Questions (Grade 7)

Download free area of any triangle worksheets (PDF), GCSE maths past paper questions and worked solutions for Area of any triangle (7L). This is a Grade 7 geometry topic from the GCSE questions by topic collection for Higher tier GCSE Maths (Edexcel, AQA, OCR and IGCSE).

The free PDF worksheets table below brings together printable question booklets (Qs) and worked answers or mark schemes (Ans) from Maths Genie, Maths4Everyone, Corbett Maths, Dr Frost, 1st Class Maths, Maths Takeaway, Maths DIY, Dr Austin, E Classroom and PMT, along with past paper question booklets.

Below the worksheet links you can read our area of any triangle revision notes and worked examples with diagrams, try real GCSE past paper area of any triangle questions with step-by-step solutions, or download a PDF of all area of any triangle worksheet links.

Free Area of any triangle PDF Worksheets & Answers

Grade 7 • Topic 7L
Resource Questions Answers
GCSE past paper questions & solutions
Qs Ans
Graded exam questions & solutions
Qs Ans
GCSE 9–1 practice booklet & solutions
Qs Ans
Practice Questions & answers
Qs Ans
Textbook Exercise & answers
Qs Ans
GCSE worksheet & solutions
Qs Ans
Edexcel exam questions & solutions
Qs Ans
AQA exam questions & solutions
Qs Ans
GCSE Maths Takeaway exam questions
Qs Ans
Exam-style booklet & solutions
Qs Ans
Practice grid / worksheet & answers
Qs Ans
GCSE topic booklet & answers
Qs Ans
PMT (Edxl)
Edexcel GCSE topic questions & solutions
Qs Ans
PMT (AQA)
AQA GCSE topic questions & solutions
Qs Ans
PMT (IGCSE)
Edexcel IGCSE topic questions & solutions
Qs Ans
Interactive online lesson & practice
Page
Self-marking online worksheet
Page
GCSE Maths Grade 7 Revision Notes & Method

Guide to Area of any triangle: Explanation, Diagrams & Worked Examples

Download Printable One Page Guide (PDF)

Explanation:

The area of any triangle can be found using Area = 12ab sin C, where a and b are two sides and C is the included angle sandwiched directly between them. If you are given two angles instead of the included angle, use angles in a triangle (180°) to find the included angle first.

When working backwards from a given area to find an unknown angle C, remember that sin(180° − θ) = sin θ: if the question states the angle is obtuse, subtract the calculator's acute angle from 180°.

Example 1: Find the area of a triangle with sides 8.5 cm and 11.2 cm and included angle 64° (3 s.f.).

64° 8.5 cm 11.2 cm

Solution:

Substitute a = 8.5, b = 11.2, C = 64°:
Area = 12 × 8.5 × 11.2 × sin 64°
Area = 47.6 × sin 64° = 42.7826... cm2
Answer: 42.8 cm2 (3 s.f.)

Example 2: A triangle has sides 9 cm and 12 cm and area 45 cm2. Given angle C is obtuse, find C (1 d.p.).

Solution:

12 × 9 × 12 × sin C = 45 ⇒ 54 sin C = 45
sin C = 4554 = 56
Acute angle = sin−1(56) = 56.442...°
Obtuse angle C = 180° − 56.442...° = 123.557...°
Answer: 123.6° (1 d.p.)
Scanned GCSE Exam Questions & Worked Solutions

GCSE Past Paper Area of any triangle Questions & Answers

Past Paper Example 1 GCSE Jun 2019 3H Q14 4 marks
The diagram shows a rectangle, ABDE, and two congruent triangles, AFE and BCD.
30°30°24 cm24 cmABCDEF
area of rectangle ABDE = area of triangle AFE + area of triangle BCD
AB : AE = 1 : 3
Work out the length of AE.
Worked Solution & Mark Scheme (4 marks)
Area of 2 triangles = 2 × (1/2 × 24 × AE × sin 30°) = 12 × AE M2
Area of rectangle = AB × AE = 12 × AE ⇒ AB = 12 cm M1
Since AB : AE = 1 : 3, AE = 3 × 12 = 36 cm A1
Answer: 36 cm
Past Paper Example 2 GCSE Jun 2025 3H Q14 2 marks
Here is triangle ABC.
35°ABC8.3 cm9.8 cm
Calculate the area of triangle ABC.
Give your answer correct to 3 significant figures.
Worked Solution & Mark Scheme (2 marks)
Area = 1/2 × b × c × sin A = 1/2 × 8.3 × 9.8 × sin(35°) = 40.67 × 0.573576... = 23.327... M1
⇒ 23.3 cm² (3 s.f.). A1
Answer: 23.3 cm²
Past Paper Example 3 GCSE Jun 2017 3H Q15 5 marks
ABC45°(2x – 1) metres(x + 3) metres
The area of triangle ABC is 6√(2) m2.
Calculate the value of x.
Give your answer correct to 3 significant figures.
The area of triangle ABC is 6√(2) m2.
Calculate the value of x.
Give your answer correct to 3 significant figures.
Worked Solution & Mark Scheme (5 marks)
Area = 1/2 × (x + 3)(2x – 1) × sin 45° = 6√2. Since sin 45° = √2 / 2, (1/2)(√2 / 2)(2x² + 5x – 3) = 6√2 M2
⇒ 2x² + 5x – 3 = 24 M2
⇒ 2x² + 5x – 27 = 0. Using quadratic formula: x = (–5 + √(25 – 4(2)(–27))) / 4 = (–5 + √241) / 4 = 2.631... = 2.63. A1
Answer: 2.63

← 7K Iteration

Back to GCSE questions by topic

7M The sine rule →