a wooden belan was made from a big cylinder and 2 equal small cylinder to flatten the dough as shown find sa of belan
Answers
Answer:
1001 sqcm
Step-by-step explanation:
the belan is made of three cylinders
one with diameter of 7cm and length of 30 cm
two cylinders with dia of 3.5 cm and length 12 cm
we have to find the surface area of belan
we will find it in two parts
1. curved surface area
curved surface area of cylinder is given by 2πrh
curved area of big cylinder = 2*(22/7)*(7/2)*30
= 660 sqcm
curved area of two small thin cylinders
= 2*2*(22/7)*(3.5/2)*12
= 264 sqcm
total curved area = 660+264
= 924 sqcm
2. Flat surface area
the two thin cylinders have one flat area open and one joined with belan
open surface area of thin cylinders
= 2*(22/7)*(3.5/2)^2
= 2*(22/7)*(3.5/2)*(3.5/2)
=38.5/2
= 19.25 sqcm
Flat surface area of big cylinder
= {( one side flat area of big cylinder) - one side (flat area of small cylinder)}*2
= {(22/7)*(7/2)*(7/2) - (22/7)*(3.5/2)*(3.5/2)} *2
= (22/7)*(1/4)*2*(7^2 - (3.5)^2)
= (11/7)* 10.5*3.5
= 11*10.5*0.5
= 57.75 sqcm
total flat area = 19.25+57.75 = 77 sqcm
Hence total surface area of belan
=total curved area + total flat area
= 924+77
= 1001 sqcm