Math Problem Statement

People of Khejadli village take good care of plants, trees, and animals. They say that plants and animals can survive without us, but we cannot survive without them. Inspired by her elders, Amrita marked some land and depicted a circular area with two smaller circles inside. The dimensions given were a large circle with a diameter of 14 cm and two smaller circles each having a radius of 7/4 cm.

Solution

The problem shows a circular area with a diameter of 14 cm containing two smaller circles with a radius of 74cm\frac{7}{4} \, \text{cm} each. It likely involves finding an area difference or some similar calculation based on the geometry provided.

Let me analyze and solve it step by step:

Step 1: Find the area of the large circle

The radius of the large circle is: Radius=Diameter2=142=7cm.\text{Radius} = \frac{\text{Diameter}}{2} = \frac{14}{2} = 7 \, \text{cm}.

The area of a circle is given by: Area=πr2.\text{Area} = \pi r^2.

For the large circle: Arealarge=π(7)2=49πcm2.\text{Area}_{\text{large}} = \pi (7)^2 = 49\pi \, \text{cm}^2.


Step 2: Find the area of one smaller circle

The radius of a smaller circle is given as 74cm\frac{7}{4} \, \text{cm}. The area of one smaller circle is: Areasmall=π(74)2=π4916=49π16cm2.\text{Area}_{\text{small}} = \pi \left( \frac{7}{4} \right)^2 = \pi \cdot \frac{49}{16} = \frac{49\pi}{16} \, \text{cm}^2.


Step 3: Find the total area of the two smaller circles

There are two smaller circles, so the total area is: Total Areasmall=249π16=98π16=49π8cm2.\text{Total Area}_{\text{small}} = 2 \cdot \frac{49\pi}{16} = \frac{98\pi}{16} = \frac{49\pi}{8} \, \text{cm}^2.


Step 4: Find the shaded area

The shaded area is the area of the large circle minus the total area of the two smaller circles: Shaded Area=ArealargeTotal Areasmall.\text{Shaded Area} = \text{Area}_{\text{large}} - \text{Total Area}_{\text{small}}.

Substituting the values: Shaded Area=49π49π8.\text{Shaded Area} = 49\pi - \frac{49\pi}{8}.

Simplify: Shaded Area=392π849π8=343π8cm2.\text{Shaded Area} = \frac{392\pi}{8} - \frac{49\pi}{8} = \frac{343\pi}{8} \, \text{cm}^2.


Final Answer:

The shaded area is: 343π8cm2or approximately 134.97cm2(using π3.14).\boxed{\frac{343\pi}{8} \, \text{cm}^2} \quad \text{or approximately } 134.97 \, \text{cm}^2 \, \text{(using } \pi \approx 3.14\text{)}.


Would you like me to explain any specific step or provide further details?


Related Questions:

  1. What would the shaded area be if the radius of the large circle were doubled?
  2. How does the shaded area change if there were three smaller circles instead of two?
  3. What fraction of the large circle's area is taken up by the smaller circles?
  4. Can you derive a formula for the shaded area if the radius of the smaller circles is a variable?
  5. How does the total area calculation change if the smaller circles overlap?

Tip:

Always ensure the units of radius and diameter are consistent before starting calculations!

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Math Problem Analysis

Mathematical Concepts

Geometry
Area of Circles
Subtraction of Areas

Formulas

Area of a circle: πr^2
Shaded area = Area of large circle - Area of smaller circles

Theorems

Basic properties of circle areas

Suitable Grade Level

Grade 8-10