Triangle Trig. Formulas

What is the Law of Cosines?

c² = a² + b² - 2abCos(C) or (side opp.)² = (side adj.)² + (other adj. side)² - 2(side adj.)(other adj. side)Cos(angle)

What is the area formula for any triangle?

A = ½ abSin(C) or A = ½(one side)(other side) sin(included angle)

What law will you use to solve SSS and SAS triangles?

Law of Cosines

What law will you use to solve ASA, AAS and SSA triangles?

Law of Sines

What kind of triangles can you use SOHCAHTOA to solve for?

Right Triangles ONLY!

What case can you have no triangle solution, one triangle solution or two possible triangle solutions?

SSA or the Ambiguous case

What is the Law of Sines?

SinA/a = SinB/b = SinC/c or sin(angle)/side opposite for each.

When solving word problems, always....

Sketch a picture of the situation.

When finding the area of a regular polygon inscribed inside a circle, what steps do you go through?

Split the regular polygon into an equal amount of triangles, depending upon how many sides the polygon has. Determine the area of one triangle, using the area formula from this chapter, with the two sides being the radii of the circle and the included angle = 360/# of triangles. Then multiply that area by how many total triangles there are. Voilà!