Answer:
Step-by-step explanation:
Left Frame
Consecutive angles (angles that are one after another) add up to 180 degrees. (The are supplementary).
9x + 6x = 180o Combine like terms
15x = 180o Divide by 15
15x/15 =180/15
x = 12
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You could do this the way it is done in the more formal proof.
9x + 6x + 9x + 6x = 360 Combine like terms: each quadrilateral = 180o
30x = 360 Perform Division Property of equality
x = 360/30 Do the division
x = 12
Right frame
The left side of line 3 is the substitution property.
<A = 9x
<B = 6x
<C = 9x
<D = 6x
The left side of line 4 is 30x. This comes from 9+6 + 9 + 6
The right side of line 5 is the division property of equality
