Since congruent angles are equal
Therefore the two figures are similar
we have
9 / 9 = 2x / x + 4
introduce cross multiplication
9 (2x) = 9(x + 4)
18x = 9*x + 9*4
18x = 9x + 36
collect the like terms
18x - 9x = 36
9x = 36
divide boths sides by 9
9x / 9 = 36/9
x = 4
The first missing variable is 2x
2 x 4
= 8
The second is x + 4
we have 4 + 4
= 8
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