Math Problem Statement

A right triangle is given with a hypotenuse of 13 cm, one leg of 5 cm, and an unknown leg. The task is to find the length of the unknown leg and to calculate the sine and cosine of a given angle θ in the triangle.

Solution

The image contains a right triangle and two trigonometric questions that need to be solved.

1. Analyzing the Triangle:

The right triangle has the following measurements:

  • Hypotenuse (PRPR) = 13 cm
  • One leg (PQPQ) = 5 cm
  • Other leg (QRQR) = xx (to be determined)

We can find QRQR using the Pythagorean theorem: PR2=PQ2+QR2PR^2 = PQ^2 + QR^2 Substituting the given values: 132=52+QR213^2 = 5^2 + QR^2 169=25+QR2169 = 25 + QR^2 QR2=144QR^2 = 144 QR=144=12 cmQR = \sqrt{144} = 12 \text{ cm} So, QR=12QR = 12 cm.

2. Trigonometric Questions:

The questions on the right side ask to find the sine and cosine of angle θ\theta.

(a) Find sinθ\sin \theta:

sinθ=oppositehypotenuse=QRPR=1213\sin \theta = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{QR}{PR} = \frac{12}{13}

(b) Find cosθ\cos \theta:

cosθ=adjacenthypotenuse=PQPR=513\cos \theta = \frac{\text{adjacent}}{\text{hypotenuse}} = \frac{PQ}{PR} = \frac{5}{13}

Final Answers:

  • QR=12QR = 12 cm
  • sinθ=1213\sin \theta = \frac{12}{13}
  • cosθ=513\cos \theta = \frac{5}{13}

Would you like more details or have any questions?

Relative Questions:

  1. How do you calculate the tangent of θ\theta for this triangle?
  2. Can you find the length of the other leg if only one leg and the hypotenuse are known?
  3. What are the values of sinθ\sin \theta and cosθ\cos \theta for θ=45\theta = 45^\circ?
  4. How does the Pythagorean theorem apply to non-right triangles?
  5. What is the relationship between sine, cosine, and tangent for any angle θ\theta?

Tip:

Always remember the basic trigonometric identities: sin2θ+cos2θ=1\sin^2 \theta + \cos^2 \theta = 1 and tanθ=sinθcosθ\tan \theta = \frac{\sin \theta}{\cos \theta}. These can help simplify many problems involving right triangles.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Pythagorean Theorem

Formulas

Pythagorean theorem: PR^2 = PQ^2 + QR^2
Sine formula: sin θ = opposite/hypotenuse
Cosine formula: cos θ = adjacent/hypotenuse

Theorems

Pythagorean Theorem

Suitable Grade Level

Grades 9-10