assume they consist of semicircles…

Mathematics Questions

For the shapes below, assume they consist of semicircles, quarter circles, and squares. Determine the area and perimeter for each shape, providing your answers as completely simplified exact values in terms of π, without approximations.

Short Answer

The area of Figure 1 is calculated by finding the area of a triangle and subtracting the area of a quarter circle, resulting in A = 36(œÄ – 2) cm¬≤. For Figure 1’s perimeter, it combines the quarter circle’s circumference and a triangle’s side length to yield P = 6(œÄ + 2‚àö2) cm, while Figure 2’s area is 576 cm¬≤ with a perimeter of P = 24(2 + œÄ) cm.

Step-by-Step Solution

Step 1: Calculate the Area of Figure 1

To determine the area of Figure 1, you need to calculate the area of a triangle and subtract the area of a quarter circle. Here’s how you do it:

  • Calculate the area of the quarter circle using the formula A = (1/4)œÄr¬≤, where r = 12 cm, giving A = 36 cm¬≤.
  • Now, find the area of the triangle with base (b) and height (h) both equal to 12 cm using A = (1/2)(b)(h), which results in A = 72 cm¬≤.
  • Finally, subtract the quarter circle area from the triangle’s area to find the total area: A = 36(œÄ – 2) cm¬≤.

Step 2: Determine the Perimeter of Figure 1

The perimeter of Figure 1 comprises the perimeter of the quarter circle and the length of one side of the triangle. Here’s the process:

  • Calculate the circumference of the quarter circle using C = (1/4)(2œÄr) which simplifies to C = 6 cm + 12‚àö2 cm.
  • Using the Pythagorean theorem, find the length of side AC, which comes out to be 12‚àö2 cm.
  • Combine these measurements: P = 6(œÄ + 2‚àö2) cm for the total perimeter.

Step 3: Analyze Figure 2’s Area and Perimeter

Figure 2 consists of a semicircle and a square, and its area and perimeter can be calculated as follows:

  • Calculate the area of the square, which is straight forward: A = b¬≤, hence A = 24¬≤ = 576 cm¬≤.
  • Finding the perimeter involves summing up two sides of the square with the circumference of the semicircles: P = 2(AB) + œÄD.
  • The final calculation gives you P = 24(2 + œÄ) cm after factoring out the common term.

Related Concepts

Area

The measure of the space inside a shape, calculated differently based on the geometry of the figure

Perimeter

The total length of the sides of a shape or the distance around a figure

Pythagorean theorem

A mathematical principle used to calculate the length of the sides of a triangle, stating that in a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides.

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