If two conical pieces of wood are cut out from a cylindrical piece of wood from two ends whose radius and height are 7cm and 10cm, then find the total surface area of the remaining part where the radius of the conical part is the same as the radius of the cylinder and the height of the cone is 60% less than the height of the cylindrical part.
If two conical pieces of wood are cut out from a cylindrical piece of wood from two ends whose radius and height are 7cm and 10cm, then find the total surface area of the remaining part where the radius of the conical part is the same as the radius of the cylinder and the height of the cone is 60% less than the height of the cylindrical part. Correct Answer 44 (10 + √65) cm<sup>2</sup>
Given:
The radius and height of cylindrical wood are 7cm and 10cm
The radius of conical part is same as the radius of cylinder
The height of cylinder is 60% less than the height of cylindrical part.
Calculation:
According to question,
Radius of cone = 7cm
And height of cone = 10 × 40% = 4
So, the slant height of cone = √(72 + 42) = √65
Now, the required surface area of the remaining part = 2πr h + 2 × πrl
So, 2 × 22/7 × 7 (10 + √65)
Hence, 44 (10 + √65) cm2