Give me the best method to solve the surface areas and volumes of ncert class 10 , Find the easiest solution of the exercise 13.1 question number 8 . Also find the simplest method of this question . From a solid cylinder whose height is 2.4 cm and diameter 1.4 cm, a conical cavity of the same height and same diameter is hollowed out. Find the total surface area of the remaining solid to the nearest cm2.
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From a solid cylinder whose height is 2.4 cm and diameter 1.4 cm, a conical cavity of the same height and same diameter is hollowed out. Find the total surface area of the remaining solid to the nearest cm2. Q.8
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The diagram for the question is as follows:
From the question we know the following:
The diameter of the cylinder = diameter of conical cavity = 1.4 cm
So, the radius of the cylinder = radius of the conical cavity = 1.4/2 = 0.7
Also, the height of the cylinder = height of the conical cavity = 2.4 cm
Now, the TSA of remaining solid = surface area of conical cavity + TSA of the cylinder
= πrl+(2πrh+πr2)
= πr(l+2h+r)
= (22/7)× 0.7(2.5+4.8+0.7)
= 2.2×8 = 17.6 cm2
So, the total surface area of the remaining solid is 17.6 cm2