The area of a triangle can be calculated with the equation: or Image:Area1.JPG However, this formula is only useful if the the base length and the perpendicular height to the base are known. There is another method for finding the area of a triangle if two side lengths are known (a and b) and the angle between them (C). (See Trigonometry for naming triangles). The formula is: These are the only two ways of finding the area of a triangle needed for GCSE or iGCSE, though there are many more (at least 7 ways in total!)