Special Right Triangles
Objectives To learn and apply the special side relationships in a 45-45-90 triangle and 30-60-90 triangle.
The 45-45-90 Triangle A 45°- 45°- 90° triangle is a special right triangle whose angles are 45°, 45°and 90°. The lengths of the sides of this triangle are in the ratio of 1:1:√2. Two equal angles will imply that two angles are also equal.
Sample Problem If the leg of a 45-45-90 triangle measures 6 ft, then what are the lengths of the two remaining sides?
Sample Problem If the hypotenuse of a 45-45-90 triangle measures 10 cm, then what are the lengths of the two legs?
Sample Problems Find the lengths of the other two sides of a right triangle if the length of the hypotenuse is inches and one of the angles is 45°. Find the length of the hypotenuse of a right triangle if the lengths of the other two sides are both 3 inches.
The 30-60-90 Triangle Another type of special right triangles is the 30°- 60°- 90° triangle. This is right triangle whose angles are 30°, 60°and 90°. The lengths of the sides of this triangle are in the ratio of 1:√3:2
Sample Problem Find the length of the hypotenuse of a right triangle if the lengths of the other two sides are 4 inches and 4√3 inches.
Sample Problem Find the lengths of the other two sides of a right triangle if the length of the hypotenuse is 8 inches and one of the angles is 30°.
Sample Problems In a 30-60-90 triangle, the side opposite the 60 degree angle has a measure 5. Find the lengths of the other two sides. In a 30-60-90 triangle, the sides opposite the 30 degree angle has a measure 5√7. Find the lengths of the other two sides.