Math Problem Statement

Work out the length x in the triangle. The area is 26 m², one side is 13 m, and the angle between them is 30°.

Solution

The problem shows a triangle with an area of 26 m², one side labeled 13 m, an angle of 30°, and another side xx that we need to find. To solve for xx, we can use the formula for the area of a triangle involving two sides and the sine of the included angle:

Area=12absin(C)\text{Area} = \frac{1}{2}ab \sin(C)

Where:

  • a=13a = 13 m (the known side),
  • b=xb = x (the unknown side),
  • C=30C = 30^\circ (the included angle),
  • Area = 26 m².

Substitute the known values into the formula:

26=12×13×x×sin(30)26 = \frac{1}{2} \times 13 \times x \times \sin(30^\circ)

We know that sin(30)=0.5\sin(30^\circ) = 0.5, so:

26=12×13×x×0.526 = \frac{1}{2} \times 13 \times x \times 0.5

Simplify the equation:

26=13x426 = \frac{13x}{4}

Multiply both sides by 4 to eliminate the denominator:

104=13x104 = 13x

Solve for xx:

x=10413=8mx = \frac{104}{13} = 8 \, \text{m}

Thus, the length of xx is 8 m.

Would you like more details or have any questions?

Related Questions:

  1. How would the solution change if the angle were different?
  2. What if the area of the triangle were larger, like 40 m²?
  3. How is the sine rule different from the area formula used here?
  4. Can this method be used for non-right triangles?
  5. How do you derive the formula for the area of a triangle using trigonometry?

Tip:

Always double-check if you are working with degrees or radians when using trigonometric functions.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Geometry

Formulas

Area of a triangle = (1/2)ab sin(C)

Theorems

Trigonometric area formula

Suitable Grade Level

Grades 9-11