Ihave been having a hard time with this question can someone explain it to me?

how do i solve this?
explain?

Hello from MrBillDoesMath!

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

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step-by-step explanation: