In the triangle ABC, AB = 12 cm and AC = 10 cm and ∠BAC =60°. What is the value of the length of side BC?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 11.13 cm.
Here we have to find the side BC, which is opposite to ∠A,
Then by law of cosines,
BC2 = AB2 + AC2 - 2 × AB × AC × cos ∠A
BC2 = 122 + 102 - 2 × 12 × 10 × 1/2
BC2 = 244 - 120 = 124
BC = 11.13 cm (approx.)