Math Problem Statement

In ΔPQR, the measure of ∠R=90°, PR = 56, RQ = 33, and QP = 65. What ratio represents the cosine of ∠P?

Solution

In a right triangle, the cosine of an angle is defined as the ratio of the length of the adjacent side to the length of the hypotenuse.

In ΔPQR, we are given:

  • ∠R = 90° (so it's a right triangle),
  • PR = 56 (this is one of the legs),
  • RQ = 33 (this is the other leg),
  • QP = 65 (this is the hypotenuse, opposite ∠R).

To find the cosine of ∠P, we use the definition of cosine: cos(P)=adjacenthypotenuse.\cos(\angle P) = \frac{\text{adjacent}}{\text{hypotenuse}}. Here, the adjacent side to ∠P is RQ (33), and the hypotenuse is QP (65). Therefore: cos(P)=RQQP=3365.\cos(\angle P) = \frac{RQ}{QP} = \frac{33}{65}.

Thus, the ratio representing the cosine of ∠P is 3365\frac{33}{65}.

Would you like further clarification or have any questions on this? Here are some related questions:

  1. How do you calculate the sine of an angle in a right triangle?
  2. What is the Pythagorean theorem, and how is it used in this problem?
  3. How can you verify if the sides of a triangle form a right triangle using the Pythagorean theorem?
  4. What other trigonometric ratios can be used to find angles in right triangles?
  5. How do you calculate the tangent of ∠P?

Tip: To easily remember trigonometric ratios in a right triangle, you can use the mnemonic SOH CAH TOA:

  • Sine = Opposite / Hypotenuse,
  • Cosine = Adjacent / Hypotenuse,
  • Tangent = Opposite / Adjacent.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Right Triangle Ratios

Formulas

cos(θ) = adjacent / hypotenuse

Theorems

Pythagorean Theorem
Trigonometric Ratios

Suitable Grade Level

Grades 8-10