Chapter 10: Problem 13
Find the area of a figure formed using a rectangle with base 3.5 yards and height 2.8 yards and a semicircle with radius 7 yards.
Short Answer
Expert verified
The approximate total area is 86.77 square yards.
Step by step solution
01
Understanding the Problem
We need to calculate the total area of a shape that consists of a rectangle and a semicircle. The given dimensions are the base and height of the rectangle and the radius of the semicircle.
02
Calculate the Area of the Rectangle
The formula for the area of a rectangle is \( A = ext{base} imes ext{height} \). Here, the base is 3.5 yards and the height is 2.8 yards. \[ A_{ ext{rectangle}} = 3.5 imes 2.8 = 9.8 ext{ square yards} \]
03
Calculate the Area of the Semicircle
The formula for the area of a circle is \( A = rac{r^2 ext{Ï€}}{2} \) where \( r \) is the radius. Since it's a semicircle, we divide the area by 2. The radius given is 7 yards. \[ A_{ ext{semicircle}} = rac{1}{2} imes ext{Ï€} imes 7^2 = rac{1}{2} imes ext{Ï€} imes 49 = 24.5 ext{Ï€} ext{ square yards} \]
04
Add the Areas Together
To find the total area of the figure, sum the area of the rectangle and the area of the semicircle. \[ A_{ ext{total}} = A_{ ext{rectangle}} + A_{ ext{semicircle}} = 9.8 + 24.5 ext{Ï€} \]
05
Approximate the Total Area
Using the approximation \( ext{Ï€} hickapprox 3.14159 \), calculate an approximate value for the area: \[ A_{ ext{total}} hickapprox 9.8 + 24.5 imes 3.14159 \approx 9.8 + 76.9695 \approx 86.7695 ext{ square yards} \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Area Calculation
Calculating the area of a shape is crucial for understanding its size and has various practical applications. To find the area of combined geometric figures, like a rectangle or a semicircle, we must determine the area of each component separately and then sum them up.
The area of a rectangle is straightforward to calculate using the formula \[ A = \text{base} \times \text{height} \]This formula simplifies the process by multiplying the length of the base by the height. In the exercise, this results in:\[ A_{\text{rectangle}} = 3.5 \times 2.8 = 9.8 \text{ square yards} \]
Meanwhile, calculating the area of a semicircle requires some extra steps. A full circle's area is, by definition:\[ A = \pi r^2 \]For a semicircle, this area is halved:\[ A_{\text{semicircle}} = \frac{1}{2} \times \pi \times r^2 \]Combining these areas gives us the total area of the figure.
The area of a rectangle is straightforward to calculate using the formula \[ A = \text{base} \times \text{height} \]This formula simplifies the process by multiplying the length of the base by the height. In the exercise, this results in:\[ A_{\text{rectangle}} = 3.5 \times 2.8 = 9.8 \text{ square yards} \]
Meanwhile, calculating the area of a semicircle requires some extra steps. A full circle's area is, by definition:\[ A = \pi r^2 \]For a semicircle, this area is halved:\[ A_{\text{semicircle}} = \frac{1}{2} \times \pi \times r^2 \]Combining these areas gives us the total area of the figure.
Rectangles and Circles
Rectangles and circles are fundamental shapes in geometry, each with unique properties. A rectangle is defined by right angles and opposite sides of equal length, making its area easy to calculate with a simple multiplication.
Circles, meanwhile, introduce a constant, \( \pi \), which is crucial in calculations involving circular shapes. The difficulty lies in accurately calculating or approximating \( \pi \) based values.- **Rectangle Properties:** - Four right angles. - Opposite sides are equal. - Easy area calculation: \( A = \text{base} \times \text{height} \)- **Circle Properties:** - Defined by its radius, which is the distance from the center to any point on the circle. - Integral in area and circumference calculations. - Area of a full circle: \( A = \pi r^2 \) - Semicircle is half that, reflecting the exercise's shape.
Circles, meanwhile, introduce a constant, \( \pi \), which is crucial in calculations involving circular shapes. The difficulty lies in accurately calculating or approximating \( \pi \) based values.- **Rectangle Properties:** - Four right angles. - Opposite sides are equal. - Easy area calculation: \( A = \text{base} \times \text{height} \)- **Circle Properties:** - Defined by its radius, which is the distance from the center to any point on the circle. - Integral in area and circumference calculations. - Area of a full circle: \( A = \pi r^2 \) - Semicircle is half that, reflecting the exercise's shape.
Mathematical Problem Solving
Solving mathematical problems often involves understanding the given figures and applying appropriate formulas. Mastery in problem-solving requires one to break down problems into smaller, manageable parts, especially when dealing with composite figures.
Success in exercises like the one above depends on the ability to:
Success in exercises like the one above depends on the ability to:
- Accurately apply area formulas for different shapes.
- Combine results logically, such as summing areas of dissimilar components.
- Approximate values like \( \pi \) where necessary for estimation.