| A | B |
|---|
| orthocenter | intersection of altitudes |
| incenter | where angle bisectors intersect |
| circumcenter | intersection of perpendicular bisectors |
| apothem | distance from the center to a side of a regular polygon |
| trapezoid | a quadrilateral with exactly 1 pair of parallel sides |
| area of a rhombus | 1/2 the product of the diagonals |
| inscribed angle | 1/2 the measure of the intercepted arc |
| central angle | equals the measure of the intercepted arc |
| right | angle inscribed in a semicircle |
| concentric circles | circles with a common center |
| perpendicular | relationship between a tangent and a radius drawn to the point of tangency |
| diameter | a chord through the center of a circle |
| isosceles | a triangle with at least 2 sides congruent |
| 3,4,&5 | sides of right triangle |
| exterior angle | equals the sum of the two remote interior angles |
| (n-2)180 | number of degrees in a convex polygon |
| 1/2 the hypotenuse | length of side opposite the 30 degree angle in a 30-60 right triangle |
| 8 | the geometric mean of 4 & 16 |
| skew | lines not contained in the same plane |
| median | segment drawn from the vertex to the midpoint of the opposite side of a triangle |
