sin 15° sin 75° = sin 75° sin 15° = sin (90° - 15°). sin 15° = cos 15°. sin 15° Multiply and divide by 2, we get = 21 2. cos 15°. sin 15° = 21 2. sin 15°. cos 15° We know that sin 2θ = 2 sin θ cos θ = 21 × sin 2(15°) = 21 × sin (30°) =21×21=41 Hence, the value of sin 15° sin 75° is =41