Find the missing length of a triangle using trig functions without a calculator

The video tutorial explains the properties of 45-45-90 triangles, focusing on the relationship between the hypotenuse and the adjacent side. It covers how to rationalize the denominator when calculating side lengths and demonstrates the use of trigonometric functions, specifically cosine, to find side lengths. The tutorial emphasizes understanding these concepts without relying on calculators, using a unit triangle to explain the cosine of 45 degrees.

In a 45-45-90 triangle, if the hypotenuse is given as X, what is the length of each leg?

• X * sqrt(2)

• X / 2

• X

• X / sqrt(2)

What is the process called when you eliminate the square root from the denominator of a fraction?

• Expanding

• Simplifying

• Factoring

• Rationalizing

Which trigonometric function is used to relate the adjacent side and hypotenuse in a right triangle?

• Secant

• Tangent

• Cosine

• Sine

What is the cosine of a 45-degree angle?

• 1

• sqrt(2) / 2

• 0

• 1 / sqrt(2)

If the hypotenuse of a 45-45-90 triangle is 30, what is the length of each leg?

• 30 / sqrt(2)

• 15 * sqrt(2)

• 30

• 15