In addition to the trigonometric ratios, what other methods can be used to solve a right triangle? Give situations for when you might want to use them

Consider the right triangle shown below.

We shall discuss two methods for solving the right triangle.

Method 1. Use of trigonometric ratios

To use trigonometric ratios requires that either m∠A or m∠B is known and that one of the sides a, b, or c is known.

Example:

Assume that m∠A is known, then m∠B = 90° - m∠A.

Also, assume that b is known.

By definition,

tan A = a/b = > a = b*tan A

cos A = b/c = > c = b/cos A, or

sin A = a/c = > c = a/sin A

Method 2. Algebraic method

When neither m∠A nor m∠B is known, then it is necessary to know the values of two sides: (a and b), (a and c), or (b and c).

The Pythagorean theorem states that

a² + b² = c²

(a) If a and b are known, then

c = √ (a² + b²)

(b) If a and c are known, then

b = √ (c² - a²)

(c) If b and c are known, then

a = √ (c² - b²)

Once all sides are known, trigonometric ratios can be used t determine m∠A and m∠B.

Example:

Because a and c are known,

sin A = a/c

A = sin⁻¹ (a/c), which can be determined from the calculator.