In the figure above, a + b + c = 360. (Note: In fact, the measures of the exterior angles of any polygon
add up to 360°.)
Area formula: The general formula for the area of a triangle is always the same. The formula is
The height is the perpendicular distance between the side that’s chosen as the base and the
opposite vertex.
In the triangle above, 4 is the height when the side of length 7 is chosen as the base.
FIVE FACTS ABOUT TRIANGLES
1. Interior angles add up to 180°.
2. Exterior angle equals sum of remote interior angles.