Question

PROCESSING BASE ANGLES OF AN ISOSCELES TRIANGLE

Answer 1

Answer:

m<A = 69°

m<C = 69°

Step-by-step explanation:

From the question given above, the following data were obtained:

AB = AC

m<B = 42°

m<A =?

m<C =?

Since:

AB = AC

Therefore,

m<A = m<C

A + B + C = 180 (sum of angles in a triangle)

C + 42 + C = 180

Collect like terms

C + C = 180 – 42

2C = 138

Divide both side by 2

C = 138 / 2

C = 69°

Finally, we shall determine m<A. This can be obtained as follow:

m<A = m<C

m<C = 69°

Therefore,

m<A = 69°