If CB and DE are parallel, the ratio of CD to DA and the ratio of BE to EA are equal. In other words, CD/DA = BE/EA . This is often a useful way of solving triangle problems and can be derived from the properties of similar triangles.
sin x = sin (180 – x) e.g. sin 130 = sin (180 – 130) = sin 50 cos x = -cos (180 – x) The Sine Rule: This works in any triangle: a = b = c sinA sinB sinC alternatively, sinA = sinB = sinC a … Read more
In any right angled triangle, for any angle: The sine of the angle = the length of the opposite side the length of the hypotenuse The cosine of the angle = the length of the adjacent side the length of the hypotenuse The tangent of the angle = the length of the opposite side the … Read more
If two shapes are similar, one is an enlargement of the other. This means that the two shapes will have the same angles and their sides will be in the same proportion (e.g. the sides of one triangle will all be 3 times the sides of the other etc.). angle A = angle D angle … Read more