Answer:
a= 15°
Step-by-step explanation:
> use the fact that the sum of angles in a triangle is 180°
> based on the picture in the small right triangle we have b° +2b° +90° =180°
b +2b +90 =180° , combine like terms
3b +90 = 180, subtract 90 from both sides of the equation
3b = 90, divide by 3 both sides of the equation
b = 30°
> angle b has a ray that continues as a line so it makes an 180° angle and we have the acute triangle so we can write that
a + a+ (180-b) =180, substitute b
2a + 180-30 =180, subtract 180 from both sides, and add 30 to both sides
2a=30, divide by 2 both sides
a= 15°
