Print PDF worksheet above, the answers are on the 2nd page of the PDF. Determine the area of the triangle to the nearest tenth. Use the appropriate Cosine formula (law of cosine) to calculate the area of the triangle. The answers are on the 2nd page of the PDF.
Trig Formula
A spreadsheet can also be used in cosines.
Prior to working with the trigonometry formulas/laws of cosines, learners should understand Pythagorean's Theorem, area and perimeters of triangles as well as having a strong understanding of angles. Typically, sin and cosine are addressed in the ninth or tenth grades in most jurisdictions.
