A triangle has sides 3 cm, 8 cm and 7 cm. What is the angle between the sides of 3 cm and 8 cm?
Answer and explanation
Correct answer: A. 60°
- Step 1: By the cosine law, c² = a² + b² - 2ab cos C.
- Step 2: cos C = (9 + 64 - 49) / (2 x 3 x 8) = 1/2, so C = 60°.
Answer
60°.
Practise more Trigonometry.
Free questions with an explanation for every one, and full timed Alberta Diploma Exams mock tests.