In triangle PQR, q = 8 cm, r = 6 cm and cos P = (frac{1}{12}). Calculate the value of p.
-
A.
(sqrt{108}) cm -
B.
9 cm -
C.
(sqrt{92}) cm -
D.
10 cm
Correct Answer: Option C
Explanation
Using the cosine rule, we have
(p^{2} = q^{2} + r^{2} – 2qr cos P)
(p^{2} = 8^{2} + 6^{2} – 2(8)(6)(frac{1}{12}))
= (64 + 36 – 8)
(p^{2} = 92 therefore p = sqrt{92} cm)
There is an explanation video available below.