How would i solve this

Question

In ABC, m A = 2x + 12, m B = x + 14, m C = 3x + 4.

Find M A?

Answers include: 25 degrees 79 degrees 62 degrees 39 degrees

Answer 1

m∠A = 2x + 12, m∠B = x + 14, m∠C = 3x + 4

 

Remember that the three angles must sum to 180°:

 

m∠A + m∠B + m∠C = 180°

2x+12 + x+14 + 3x+4 = 180

6x + 30 = 180

 

Solve for x, then use that value in the equation m∠A = 2x + 12 to find m∠A.

Answer 2

The measures of the three angles must sum to 180°.

 

m<A + m<B + m<C = 180

 

(2x + 12) + (x + 14) + (3x + 4) = 180

 

6x + 30 = 180

 

6x = 150

 

x = 25

 

Now plug in 25 for x to get the measure of each angle

 

m<A = 2·25 + 12 = 62

 

To check everything:

 

m<B = 39

 

m<C = 79

 

62 + 39 + 79 = 180