Question

Help me with the 7 th question.

Answer 1

Hello,
we calculate the area of square:
A(ABCD)=L²=14²=196 cm²

given semicircle is drawn with side of square as diameter.
so, diameter of semicircles:
d=L=14 cm
we calculate the radius of semicircle:
r=d/2=L/2=14/2=7 cm

since radius is same for semi-cicle AD,AB,BC,CD.
we calculate the area the semi-cicle:
Ac=πr²/2=7²π/2=(49×3.14)/2=153,86/2=76.93 cm²

let us mark the unshaded region as a,b,c and d (see figure)
we calculate the area of region (a+b+c+d):
A(abcd)=2A(ABCD)-4Ac;
             =(2×196)-(4×76.93);
             =392-307.72=84.28 cm²

now, we calculate the area of shaded region:
A=A(ABCD)-A(abcd)=196-84.28=111.72 cm²

Hence area of shaded region is 111.72 cm²

bye :-)

Answer 2

Diameter = 14 cm Radius = 7cm Area of one quadrant = 77/2 cm Area of one triangle =49/2 cm Area(quadrant - triangle)= 14 cm Area of shaded region =14×2×4= 112 cm I multiply it by 2 because when we subtract area of quadrant and triangle there is a area which is a half of one shaded region .there area total 4 shaded region that is why l multiply it by 4