Find the surface area of a sphere whose diameter is equal to 28 cm.
784π cm²
To find the surface area of a sphere whose diameter is 28 cm, we use the formula for the surface area of a sphere, which is \(4\pi r^2\), where \(r\) is the radius of the sphere.
First, calculate the radius by dividing the diameter by 2: \(r = \frac{28\text{ cm}}{2} = 14\text{ cm}\).
Now, substitute the radius into the formula:
\( \text{Surface Area} = 4\pi (14\text{ cm})^2 \)
Simplify this expression:
\( = 4\pi \times 196\text{ cm}^2 \)
\( = 784\pi\text{ cm}^2 \)
Thus, the surface area of the sphere is \(784\pi\text{ cm}^2\).
Important Questions from Mensuration
In a circular garden of radius 15 m, a path of 2 m wide has to be made inside the garden at the rate of ₹ 24 per sq. m. The cost of making the path is: (Take π = \(\frac{22}{7}\) )
A hollow cylinder with outer radius 4 cm and height 2 cm is made up of 1 cm thick metal sheet. What is the volume of metal used? (Take π = \(\frac{22}{7}\))
The sides of a triangular park are 60 m, 297 m and 303 m. Its area is equal to the area of a square-shaped garden. What is the perimeter (in m) of the garden?
The length and breadth of a rectangular field are in the ratio 4 : 3. If the cost of cultivating the field at ₹2 per m 2is ₹600, then the length of the field is:
A cylindrical tank has a capacity of 5632 m3. If the diameter of its base is 8 m, what is the depth of the cylindrical tank? (Use π = \(\frac{22}{7}\))
