Math Problem Statement

The shape consists of a rectangle and three quarters of a circle, where the center of the circle lies on the corner of the rectangle. Find the perimeter of the shape. Give your answer to two decimal places. Use π = 3.14.

Solution

Let’s analyze the problem and solve it step by step.

Problem Description:

  • The shape is a combination of a rectangle and three-quarters of a circle.
  • The rectangle's dimensions are 4 m (length) and 3 m (height).
  • The circle's radius is 2 m, and the circle is positioned so that three-quarters of its perimeter forms part of the shape.

We are tasked with finding the perimeter of the shape to two decimal places, and π is approximated as 3.14.


Solution:

Step 1: Perimeter of the rectangle

The perimeter of the rectangle includes:

  • Two full sides (3 m and 4 m), and
  • Two other sides, where part of the circle replaces one corner.

Thus, the linear part of the rectangle in the perimeter is: 4m (bottom)+3m (right)=7m.4 \, \text{m (bottom)} + 3 \, \text{m (right)} = 7 \, \text{m}.

Step 2: Three-quarters of the circle's circumference

The circle's radius is r=2mr = 2 \, \text{m}. The circumference of the full circle is: C=2πr=2×3.14×2=12.56m.C = 2 \pi r = 2 \times 3.14 \times 2 = 12.56 \, \text{m}.

Since only three-quarters of the circle is part of the perimeter, we calculate: Three-quarters of the circumference=34×12.56=9.42m.\text{Three-quarters of the circumference} = \frac{3}{4} \times 12.56 = 9.42 \, \text{m}.

Step 3: Total Perimeter

The total perimeter is the sum of the linear part of the rectangle and the three-quarters of the circle: Perimeter=7+9.42=16.42m.\text{Perimeter} = 7 + 9.42 = 16.42 \, \text{m}.


Final Answer:

The perimeter of the shape is: 16.42m\boxed{16.42 \, \text{m}}


Let me know if you'd like more details or have further questions. Below are some related questions to expand your understanding:

  1. How would the perimeter change if the circle were a full circle instead of three-quarters?
  2. How is the area of the shape calculated?
  3. What if the rectangle’s dimensions were different? How would that affect the perimeter?
  4. What happens to the calculation if π is used as 3.14159 instead of 3.14?
  5. How do you calculate the arc length for any fraction of a circle?

Tip: Always break down composite shapes into their basic components to simplify calculations.

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Math Problem Analysis

Mathematical Concepts

Geometry
Perimeter of composite shapes
Circle properties
Arc length calculation

Formulas

Perimeter of a rectangle = 2(length + width)
Circumference of a circle = 2πr
Arc length of a circle = (θ/360) × 2πr

Theorems

Properties of circles
Relationship between arc length and central angle

Suitable Grade Level

Grades 8-10