Answers

2016-02-20T08:27:09+05:30
Height of cylinder = total height - height of cone 26-6 = 20cm

TSA of the cylinder seperately = 2πr(r+h)
= 2
π*3*(3+20)
= 6*23
π
= 138
π sq.cm
But some of the top surface of the cone is covered with the cone's.
∴ Actual TSA = 138π-(πr²-π(radius of cone)²)
= 138π-π((3)²-(2.5²))
= 138
π - 2.75π
= 135.25
π sq.cm

The diameter of the cone is completely covered by the cylinder's.
∴ Actual TSA of cone = CSA of cone
πrl

Now, l = 
√[(r)²+(h)²]
√[(2.5)²+(6)²]
√[6.25+36]
√42.25
= 6.5cm

∴ CSA = π*2.5*6.5 = 16.25π sq.cm

Therefore TSA of total figure
= 135.25π+16.25π 
= 151.5π
= 151.5(22/7)
= 476.14 sq.cm
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