from a right circular cylinder of radius 7 cm and height 12 cm , a right cone half the height of the cylinder is removed .the base of the cone is one of the plane faces of the cylinder , their centers being the same . if the radius of base of cone is half the radius of base of cylinder , find the total surface area of the solid left​

Dear Student,

we can draw the following figure A based on the statements given in the Question.


Total surface area of solid left= Total surface area of Cylinder - Total surface area of cone.

Total Surface Area of Cylinder=2πr(h+r)
putting values in the formula we get
2×227×7×(12+7)44×19=836

Total surface area of the cone
π×r2+π×r×lfrom figure B we can apply pythagorus theorem and getl2=r2+h2l2=722+62l2=494+36l2=1934l=6.95

Total surface area of cone
227×72×72+227×72×6.95=22×74+11×6.95=38.5+76.45=114.9

Total surface area of the Solid left
=836-114.9
=721.1 cm

Regards,
 

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