Question

Find m<B. Please help me​

Answer 1

With the markings on the triangle, we know that this is an isosceles triangle. This makes m∠B=m∠C.

Let x=m∠B. We know that all the angles in a triangle must add up to 180°

m∠A + m∠B + m∠C = 180

We know that m∠A=118°, m∠B=x, and m∠C=m∠B=x. Using this information, the equation changes to:

$118+x+x=180$

$2x+118=180$

Subtract both sides by 180

$2x=62$

Divide both sides by 2

$x=31$

Since x=31, m∠B must be 31°.

This explanation might be a bit confusing, so let me know if you need any clarifications, thanks!

~ Padoru