Math Problem Statement

The shaded segment is formed by an arc BC of a circle with radius 1.6m, subtending an angle of 4π/9 radians at its center A. Find the area of the shaded segment, correct to 3 significant figures.

Solution

To find the area of the shaded segment in the given circle, we need to use the formula for the area of a segment. The area of the shaded segment is the difference between the area of the sector AsectorA_{\text{sector}} and the area of the triangle AtriangleA_{\text{triangle}}.

Step 1: Area of the sector

The area of a sector is given by: Asector=12r2θA_{\text{sector}} = \frac{1}{2} r^2 \theta where rr is the radius of the circle, and θ\theta is the angle in radians.

From the image:

  • r=1.6mr = 1.6 \, \text{m}
  • θ=4π9radians\theta = \frac{4\pi}{9} \, \text{radians}

Substituting these values: Asector=12×(1.6)2×4π9A_{\text{sector}} = \frac{1}{2} \times (1.6)^2 \times \frac{4\pi}{9}

Step 2: Area of the triangle

The area of the triangle can be calculated using the formula: Atriangle=12r2sin(θ)A_{\text{triangle}} = \frac{1}{2} r^2 \sin(\theta) Substitute the known values: Atriangle=12×(1.6)2×sin(4π9)A_{\text{triangle}} = \frac{1}{2} \times (1.6)^2 \times \sin\left(\frac{4\pi}{9}\right)

Step 3: Area of the shaded segment

The area of the shaded segment is: Asegment=AsectorAtriangleA_{\text{segment}} = A_{\text{sector}} - A_{\text{triangle}}

I will now calculate these areas and find the final answer.The area of the shaded segment is approximately 0.527m20.527 \, \text{m}^2, correct to 3 significant figures.

Would you like more details or have any questions?

Here are 5 related questions to explore further:

  1. How would the formula change if the angle was given in degrees instead of radians?
  2. What is the significance of using radians in calculations for circular areas?
  3. How can you find the area of a sector when only the arc length is given?
  4. How does increasing the radius affect the area of the shaded segment?
  5. How would you calculate the perimeter of the shaded segment?

Tip: For accurate calculations in geometry, always ensure that angles are in the correct units (radians or degrees) based on the formulas you're using.

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Math Problem Analysis

Mathematical Concepts

Circle geometry
Sectors
Trigonometry

Formulas

Area of sector = (1/2) * r^2 * θ
Area of triangle = (1/2) * r^2 * sin(θ)
Area of segment = Area of sector - Area of triangle

Theorems

Sector area formula
Sine rule in triangles

Suitable Grade Level

Grades 9-12