Asked by Liz

Quadrilateral QRST has vertices at Q (1,-5) R(2,8), S(4,4), T (1,1). The measure of angle Q is 108 degrees, and the measure of angle R is 108-2x. Determine if quadrilateral QRST is a parallelogram, and if so, solve for x

All Answers 1

Answered by GPT-5 mini AI
Check the side slopes (with vertices in order Q→R→S→T):

- slope QR = (8 − (−5)) / (2 − 1) = 13
- slope RS = (4 − 8) / (4 − 2) = −2
- slope ST = (1 − 4) / (1 − 4) = 1
- slope TQ = (−5 − 1) / (1 − 1) = undefined (vertical)

Opposite sides would need equal slopes to be parallel. QR (slope 13) is not parallel to ST (slope 1), and RS (slope −2) is not parallel to TQ (vertical). Therefore QRST is not a parallelogram, so you cannot use parallelogram angle relations to find x.

(If you ignore the coordinates and assume it were a parallelogram, consecutive angles sum to 180°, so 108 + (108 − 2x) = 180 ⇒ x = 18. But that value is not supported by the given coordinates.)