the circular portion of the semicircles find area and perimeter
Answers
Step-by-step explanation:
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Step-by-step explanation:
diameter of semicircles =21
radius,r =21/2
perimeter of semicircle = 2pi r/2
perimeter of other semicircle = 2 pi r /2
as the length of diameter is same for both semicircles,
r is same for both
perimeter of both semicircles
= 2pi r/2 ×2 =2×pi × r
= 2×22/7×21/2
= 66 cm
b, breadth of rectangle =36-(2×r)
=36-(2×21/2)
= 36-21= 15
length,l = 21
perimeter of rectangle
=2×(l+b)=2×(21 +15)
=2×36=72
total perimeter
= perimeter of rectangle +
perimeter of 2 semicircles
=72+66=138
area of rectangle = l*b
= 21×15=315
area of both semicircles
= (Pi ×r²)/2+pi×r²/2=pi×r²
= 22/7×(21/2)²
= 22x21²/(7×4)
= 11×3×21/2 =346.5
total area
= area of rectangle + area of semicircles
=315+346.5=661.5