If \( \cos \theta = \frac{a}{b} \), find \( 1 + \tan^2 \theta \)

Simplify \( \frac{0.0324 \times 0.00064}{0.48 \times 0.012} \)

If P = 18, Q = 21, R = -6 and S = -4, Calculate \( \frac{(P-Q)^3+S^2}{R^3} + S^2 \)

Find the smallest number by which 252 can be multiplied to obtain a perfect square

Divide the L.C.M of 48, 64, and 80 by their H.C.F

Find the reciprocal of \( \frac{\frac{2}{3}}{\frac{1}{2}+\frac{1}{3}} \)

Evaluate (212)3 - (121)3 + (222)3

If Musa scored 75 in biology instead of 57, his average mark in four subjects would have been 60. What was his total mark?

Two chords QR and NP of a circle intersect inside the circle at x. If RQP = 37o, RQN = 49o and QPN = 35o, find PRQ