Math Problem Statement

include Pythagorean Theorem to solve and find the area

Find the area enclosed by the figure. Use 3.14 for π and do not round your answer. The figure is not to scale.

Solution

To find the area of this shape, which is a combination of a rectangle and a half-circle, we'll use a few steps and employ the Pythagorean theorem to verify dimensions if necessary. Let's proceed as follows:

Step 1: Find the Radius of the Half-Circle

The given dimensions indicate that the length from the left side to the right edge of the rectangle is 7cm7 \, \text{cm}. Since the rectangle has a width of 4cm4 \, \text{cm}, this leaves a radius of the half-circle of: r=7cm4cm=3cmr = 7 \, \text{cm} - 4 \, \text{cm} = 3 \, \text{cm}

Step 2: Calculate the Area of the Rectangle

The area ArectangleA_{\text{rectangle}} of the rectangle is given by: Arectangle=width×height=4cm×6cm=24cm2A_{\text{rectangle}} = \text{width} \times \text{height} = 4 \, \text{cm} \times 6 \, \text{cm} = 24 \, \text{cm}^2

Step 3: Calculate the Area of the Half-Circle

The area of a full circle with radius r=3cmr = 3 \, \text{cm} is: Acircle=πr2=3.14×(3)2=3.14×9=28.26cm2A_{\text{circle}} = \pi r^2 = 3.14 \times (3)^2 = 3.14 \times 9 = 28.26 \, \text{cm}^2 Since we only have a half-circle, we divide this by 2: Ahalf-circle=28.262=14.13cm2A_{\text{half-circle}} = \frac{28.26}{2} = 14.13 \, \text{cm}^2

Step 4: Add the Areas

Now, we add the area of the rectangle and the half-circle to find the total area of the figure: Atotal=Arectangle+Ahalf-circle=24cm2+14.13cm2=38.13cm2A_{\text{total}} = A_{\text{rectangle}} + A_{\text{half-circle}} = 24 \, \text{cm}^2 + 14.13 \, \text{cm}^2 = 38.13 \, \text{cm}^2

Answer

The total area enclosed by the figure is: 38.13cm2\boxed{38.13 \, \text{cm}^2}

Would you like further details or have any other questions?


Relative Questions:

  1. How would the area change if the radius of the half-circle were different?
  2. How is the Pythagorean theorem used in verifying the dimensions of composite shapes?
  3. What if the shape was a full circle instead of a half-circle?
  4. How do different values of π\pi affect area calculations?
  5. Can this method be generalized for other composite shapes?

Tip:

When dealing with composite shapes, break down each part, calculate their areas individually, and then sum them to find the total area.

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Math Problem Analysis

Mathematical Concepts

Geometry
Area of Composite Shapes
Circles
Rectangles

Formulas

Area of a rectangle: A = width × height
Area of a circle: A = πr²
Area of a half-circle: A = (πr²) / 2

Theorems

Pythagorean Theorem (implicitly used to verify dimensions if necessary)

Suitable Grade Level

Grade 6-8