Question

Help, please!! What is mA?

Answer 1

Answer:

38°

Step-by-step explanation:

The measure of required angle can be obtained by using cosine law.

From the given triangle we find that:

a = 5, b = 3, c = 7,

Since,

cos (A) = (b^2 +c^2 - a^2) /2bc

Therefore,

cos (A) = (3^2 + 7^2 - 5^2) /(2*3*7)

cos (A) = (9 + 49 - 25) /(42)

cos (A) = (33) /(42)

cos (A) = 0.785714286

A = arccos(0.785714286)

A = 38.213210675°

A = 38°