How to Master the Pythagorean Theorem and Right Triangles

• 45-45-90 triangle: This is an isosceles right triangle where the two legs are congruent, and the hypotenuse is \(\sqrt{2}\) times the length of one leg.
• 30-60-90 triangle: In this triangle, the sides are in the ratio of \(1: \sqrt{3}: 2\), with the smallest side opposite the \(30^\circ\) angle and the longest side being the hypotenuse.

Examples

Practice Questions:

1. In a right triangle, if one leg measures \(9 \text{ cm} \) and the hypotenuse measures \(15 \text{ cm} \), find the length of the other leg.
2. Calculate the longer leg in a 30-60-90 triangle if the shorter leg (opposite the \(30^\circ\) angle) measures \(4 \text{ cm} \).

1. Using the Pythagorean theorem, \( b^2 = 15^2 – 9^2 = 144 \) so \( b = 12 \text{ cm} \).
2. The longer leg (opposite the \(60^\circ\) angle) is \(\sqrt{3}\) times the shorter leg, so it measures \(4 \times \sqrt{3} \approx 6.93 \text{ cm} \).