- find the area for the triangle-find the area for the parallelogram

Statement: The area of a triangle can be expressed using the lengths of two sides and the sine of the included angle. Areas = 1/2 ab sin C. You may see this referred to as the SAS formula for the area of a triangle. With this new formula, we no longer have to rely on finding the altitude (height) of a triangle in order to find its area. Now, if we know two sides and the included angle of a triangle, we can find the area of the triangle. This is a valuable new formula! Example 1: Given the triangle at the right, find its area. Express the answer to the nearest hundredth of a square unit. S A = - absin C When using your graphing calculator, be 12 A = -(12)(18) sin 550 sure you are in DEGREE mode, or using the degree 550 symbol. R 18 A ~88.47 sq. units Let a = ST, b = RT, and C = LRTS