Question

Find a of this angle.

Answer 1

A is 85 ° because 2x is 38, 38 + 57 is 95 ° and 180-95 is 85 °

Answer 2

In a triangle, the total angle is 180 degrees. A straight line is always 180 degrees. With this in mind, the following can be obtained:

$a + 2x + {57}^{o} = {180}^{o} \\ 5x + a = {180}^{o}$

These are simultaneous equations.

$a + 2x + {57}^{o} = 5x + a \\ 3x = {57}^{o} \\ x = {19}^{o} \\ 5x + a = {180}^{o} \\ 5( {19}^{o} ) + a = {180}^{o} \\ a = {85}^{o}$