Answer:
YZ = 28
Step-by-step explanation:
A proportion involving the known and unknown sides is ...
TR/ST = ZY/SZ
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This proportion uses SZ, which is not shown on the diagram. The length of SZ can be found from ...
SZ +ZT = ST . . . . . . . segment sum theorem
SZ + 5 = 40 . . . . with given values
SZ = 35 . . . . . subtract 5
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So, the proportion with values filled in is ...
(3x -7)/40 = (2x +2)/35
7(3x -7) = 8(2x +2) . . . . . . . multiply by 280
21x -49 = 16x +16 . . . . . . . eliminate parentheses
5x = 65 . . . . . . . . . . add 49 -16x
x = 13 . . . . . . . . divide by 5
YZ = 2x +2 = 2(13) +2
YZ = 28
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Additional comment
RT = 3x -7 = 3(13) -7 = 32
