WAEC - Mathematics (2001 - No. 37)

PQRS is a rhombus of side 16cm. The diagonal |QS| = 20cm. Calculate, correct to the nearest degree, ∠PQR

51^o

64^o

77^o

103^o

cos\(\alpha\) = \(\frac{10}{16}\) = 0.625

\(\alpha\) = cos^-1(0.625)

= 51.3^o

∠PQR = 2\(\alpha\)

= 2(51.3^o)

= 102.6

= 103^o