Math Problem Statement

In right triangle ABC with right angle C, AB = 15 and AC = 9 find sin(A) and cot(A)

Solution

In a right triangle, we can find trigonometric ratios using the known sides. You are given:

  • Right triangle ABCABC with C=90\angle C = 90^\circ,
  • AB=15AB = 15 (hypotenuse),
  • AC=9AC = 9 (adjacent to angle AA).

To find sin(A)\sin(A) and cot(A)\cot(A), we first need to calculate the length of side BCBC, which is the opposite side to A\angle A, using the Pythagorean theorem:

AB2=AC2+BC2AB^2 = AC^2 + BC^2 152=92+BC215^2 = 9^2 + BC^2 225=81+BC2225 = 81 + BC^2 BC2=144BC^2 = 144 BC=12BC = 12

Now that we know BC=12BC = 12, we can calculate:

1. sin(A)\sin(A):

sin(A)=oppositehypotenuse=BCAB=1215=45\sin(A) = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{BC}{AB} = \frac{12}{15} = \frac{4}{5}

2. cot(A)\cot(A):

cot(A)=adjacentopposite=ACBC=912=34\cot(A) = \frac{\text{adjacent}}{\text{opposite}} = \frac{AC}{BC} = \frac{9}{12} = \frac{3}{4}

Thus: sin(A)=45,cot(A)=34\sin(A) = \frac{4}{5}, \quad \cot(A) = \frac{3}{4}

Would you like more details or have any questions?

Here are five related questions:

  1. How do we calculate cos(A)\cos(A) in a right triangle?
  2. What is the value of tan(A)\tan(A)?
  3. Can you find sin(B)\sin(B) and cot(B)\cot(B) in this triangle?
  4. How do you derive the Pythagorean identity from these values?
  5. How would trigonometric values change if the triangle's sides were scaled?

Tip: For any right triangle, remember that the sine and cosine of an angle are simply the ratios of two sides, and these ratios do not depend on the actual size of the triangle, only on the angle itself.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Right Triangles

Formulas

Pythagorean Theorem: AB^2 = AC^2 + BC^2
Sine: sin(A) = opposite / hypotenuse
Cotangent: cot(A) = adjacent / opposite

Theorems

Pythagorean Theorem

Suitable Grade Level

Grades 9-11