View more at http://www.MathAndScience.com. In this lesson, you will learn additional formulas to calculate the area of a triangle in trigonometry. We previously learned that the area of a triangle is given as 1/2 times the base times the height of the triangle, A = 1/2(b)(h). Here we present several additional formulas to be used when we don't have the height available. Perhaps we are given one of the angles of the triangle instead of the height. We will learn how to calculate the area of a triangle in many more cases.