Trigonometric Ratios Of Complementary Angles We know complementary angles are pair of angles whose sum is 90° Like 40°, 50°, 60°, 30°, 20°, 70°, 15°, 75° ; etc, Formulae: sin (90° – θ) = cos θ, cot (90° – θ) = tanθ cos (90° – θ) = sin θ, sec (90° – θ) = cosec θ tan (90° – θ) = cot θ, cosec (90° – θ) = sec θ Trigonometric Ratios Of … [Read more...] about Trigonometric Ratios Of Complementary Angles