Question

17. Tick the correct answer and justify: In ABC, AB = 6root3 cm, AC=12 cm and BC = 6 cm.
The angle B is:
(A) 120°
(B) 60°
(C) 90°
(D) 45°
​

Answer 1

Answer:

C)90°

Step-by-step explanation:

90°

hope it will help

Answer 2

SOLUTION

In ∆ABC, AB =

6

√

3

63

cm, AC = 12 cm, BC = 6 cm.

AB2 = (\[6\sqrt{3}\)2 = 108

AC2 = (12)2 = 144

BC2 = (6)2 = 36

108 + 36 = 144

In a triangle, if the square of one side is equal to the sum of the squares of the remaining two sides, then the triangle is a right angled triangle.

In a right angled triangle, if one side is half of the hypotenuse then the angle opposite to that side is 30°.

Here, BC is half of AC.

Thus, measure of ∠A is 30°

Hence, the correct option is (A).