Calculate with the Law of Sines and Cosines in GeoGebra
When you are asked to find the side lengths, the angles, or the area of a triangle using either
you can use GeoGebra to do the calculation for you. You can read more about the formulas themselves in the entries above. In this entry, we’ll look at how to use them in GeoGebra.
GeoGebra Instruction 1
- 1.
- Open
CASunder
Viewin
Menu. - 2.
- Find out which of the formulas you need to use.
- 3.
- Type the expression or equation you’ve been given directly into
CASand then pressSolve Numerically
. Sometimes, you get two answers. If one of the answers is less than zero, then ignore this answer and use the other, since neither lengths nor angles can be negative.
If both are greater than zero, then the problem has two solutions.
Note! If your angles are in degrees, use the degree symbol (keyboard shortcut alt+o in Windows) when you type them in CAS. If you don’t, GeoGebra will calculate the answers in radians instead, which is another unit for measuring angles. If the unknown is supposed to be an angle in degrees, you need to place a symbol next to as well.
