a missing side in a right-angled triangle when another side and an angle are known. a missing angle in a right-angled triangle when two sides are known. In these formulae, the Greek letter θ (theta) ...

Being able to identify which formula to use, sine or cosine, and when, is necessary to answer questions on this topic successfully. Check you are confident in how to use the sine and cosine rules.

With all due respect to Pythagoras, newly uncovered evidence suggests that his famous theorem, used to calculate the lengths of each side of a right triangle, might be 1,000 years older than him. That ...