Question

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Answer 1

Because <R is 90 degrees, you can use RQ as one of the legs of the larger triangle formed by the two smaller ones.
Applying the Pythagorean theorem, if (RQ^2) + (RP^2) = (PQ^2), then ___^2 + 6^2 = 12^2.

Answer 2

I haven't learned the Pythagorean theorem yet... so how am I supposed to solve this?

Answer 3

because triangle QRS and PQR is similar (all angles were same)
use the proportion :
QS/QR = QR/QP
x/6 = 6/12
x/6 = 1/2
x = .....