m∡A = 70º
1) Considering that the Sum of the interior angles within a triangle is always 180º
2) We can write the following, and solve for x
x+80 + x +80 +40 = 180
2x +160 +40 = 180
2x + 200 = 180
2x =180-200
2x= -20
x=-10
3) So since angle A = x +80, we can plug it into that the value of x
m∡A = x +80º
m∡A=-10+80
m∡A = 70º
Answer:
Step-by-step explanation:
Since RQT=155
4x-20+3x+14=155
7x-6=155
7x=161
x=23
The answer is B
Since you know that BOD is a right angle add 12 And 15 and subtract your answer from 90