Math Problem Statement

Calculate the surface area of a composite shape consisting of a cylinder with hemispherical ends, using pi = 22/7.

Solution

The problem in the image asks to calculate the surface area of a composite shape, which seems to be a cylinder with two hemispherical ends. It also specifies to use π=227\pi = \frac{22}{7}.

Given dimensions:

  • Length of the cylinder (without hemispheres) = 35 cm
  • Radius of the base (and hemisphere) = 7 cm

Step-by-Step Solution:

  1. Surface Area of the Cylinder (without the hemispheres): The surface area of a cylinder (lateral area) is given by: Lateral Area of Cylinder=2πrh\text{Lateral Area of Cylinder} = 2 \pi r h where:

    • r=7cmr = 7 \, \text{cm} (radius),
    • h=35cmh = 35 \, \text{cm} (height of the cylindrical part).

    Substituting the values: Lateral Area=2×227×7×35=2×22×35=1540cm2\text{Lateral Area} = 2 \times \frac{22}{7} \times 7 \times 35 = 2 \times 22 \times 35 = 1540 \, \text{cm}^2

  2. Surface Area of the Two Hemispheres: The total surface area of two hemispheres is the same as the surface area of a full sphere. The surface area of a sphere is given by: Surface Area of Sphere=4πr2\text{Surface Area of Sphere} = 4 \pi r^2 where r=7cmr = 7 \, \text{cm}.

    Substituting the values: Surface Area of Hemispheres=4×227×72=4×227×49=4×154=616cm2\text{Surface Area of Hemispheres} = 4 \times \frac{22}{7} \times 7^2 = 4 \times \frac{22}{7} \times 49 = 4 \times 154 = 616 \, \text{cm}^2

  3. Total Surface Area: The total surface area is the sum of the lateral area of the cylinder and the surface area of the two hemispheres: Total Surface Area=1540+616=2156cm2\text{Total Surface Area} = 1540 + 616 = 2156 \, \text{cm}^2

Final Answer:

The surface area of the composite shape is 2156 cm².


Would you like further details on this calculation or explanations? Here are some related questions for practice:

  1. How do you calculate the volume of a cylinder with hemispherical ends?
  2. What is the formula for the volume of a hemisphere?
  3. How does changing the radius affect the surface area of a cylinder?
  4. What is the difference between lateral and total surface area in a cylinder?
  5. Can you apply this formula to other composite shapes, like a cone?

Tip: Always double-check the units and dimensions when working with surface area to avoid errors in calculations!

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Math Problem Analysis

Mathematical Concepts

Geometry
Surface Area
Cylinders
Hemispheres

Formulas

Lateral Area of Cylinder = 2 * pi * r * h
Surface Area of Sphere = 4 * pi * r^2
Surface Area of Two Hemispheres = Surface Area of Sphere

Theorems

Surface Area of Cylinders and Spheres

Suitable Grade Level

Grades 8-10