Answer:
Step-by-step explanation:
Find c if ∠PQR = 90°?
I will ASSUME you mean point P is at (3. c)
slope of PQ is (2 - c) / (9 - 3) = (2 - c) / 6
slope of QR is (11 - 2) / (3c - 9) = 9 / (3c - 9)
perpendicular lines have negative reciprocal slopes.
(2 - c) / 6 = -1(3c - 9)/9
9(2 - c) = -6(3c - 9)
18 - 9c = -18c + 54
9c = 36
c = 4
