Question

Find the measure of the largest angle in ABC if a = 12, b = 8 and c = 13.

Answer 1

`C=78.28^(\circ \:)`

Explanation:

We are given a triangle

whose sides are

a=12

b=8

c=13

Since, c is largest among them

So, angle C must be largest angle

we can find angle C

we can use law of cosine formula

`cos(C)=(a^2+b^2-c^2)/(2ab)`

now, we can plug values

`cos(C)=(12^2+8^2-13^2)/(2* 12* 8)`

`cos(C)=(13)/(64)`

now, we can find angle

we get

`C=78.28^(\circ \:)`