PQRS is a rhombus of side 16cm. The diagonal |QS| = 20cm. Calculate, correct to the nearest degree, ∠PQR
A.
51o
B.
64o
C.
77o
D.
103o
Correct answer is D
cos\(\alpha\) = \(\frac{10}{16}\) = 0.625
\(\alpha\) = cos-1(0.625)
= 51.3o
∠PQR = 2\(\alpha\)
= 2(51.3o)
= 102.6
= 103o