Hello from MrBillDoesMath!
Answer:
a = 35
b = 25
Discussion:
From the topmost triangle:
90 + 55 + a = 180 =>
145 + a = 180 => subtract 145 from both sides
a = 180 - 145 = 35 (*)
From the bottom triangle we have
a + b + 120 = 180 => substitute a = 35 from above calculation
35 + b + 120 = 180 => 120 + 35 = 155
155 + b = 180 => subtract 155 from both sides
b = 180 - 155 = 25 (**)
Note the angle at the top of the bottom triangle is a vertical angle so equals "a"
Finally, from (*) and (**) we have a = 35 and b = 25
Thank you,
MrB
