12 write the greatest 4-digit number using different digits with tens digit smallest natural number and unit is five times the tens digit.
Answers
Answer:
Given:-
The circumference of circle is 132 m, find the area.
To Find:-
The area.
Note:-
●》As for finding area, radius is to be known and radius = \frac{Diameter}{2}
2
Diameter
, but diameter is also not known so we'll calculate from circumference formula i.e. Circumference of a circle = 2πr ( π = \frac{22}{7} )(π=
7
22
)
●》For finding some unknown values, a known values needs to be rearranged and signs are also changed or not. For example - multiple becomes divisional ( signs do not change ), divisional becomes multiple ( signs do not change )
●》Area of a circle = πr² ( π = \frac{22}{7} )(π=
7
22
)
Solution:-
[ For Radius ]
\huge\red{Circumference = 132 m, \ \ Radius = ?, Let \ \ Radius = "x"}Circumference=132m, Radius=?,Let Radius="x"
☆ According to note first point and π = \frac{22}{7}π=
7
22
~
▪︎Circumference \ \ of \ \ a \ \ circle = 2πrCircumference of a circle=2πr
▪︎132 m = 2 × \frac{22}{7} × x132m=2×
7
22
×x
▪︎132 m = \frac{44}{7} × x132m=
7
44
×x
☆ According to note second point ( rearrangement )~
▪︎132 m × 7 = 44 × x132m×7=44×x
▪︎924 m = 44 × x924m=44×x
▪︎924 m ÷ 44 = x924m÷44=x
☆ After doing division~
▪︎21 m = x21m=x
\huge\pink{Radius = x = 21 m}Radius=x=21m
______________________
[ Now, Area ]
☆ According to note third point and π = \frac{22}{7}π=
7
22
~
▪︎Area \ \ of \ \ a \ \ circle = πr²Area of a circle=πr²
▪︎Area \ \ of \ \ a \ \ circle = \frac{22}{7} × ( 21 m )²Area of a circle=
7
22
×(21m)²
▪︎Area \ \ of \ \ a \ \ circle = \frac{22}{7} × 21 m × 21 mArea of a circle=
7
22
×21m×21m
▪︎Area \ \ of \ \ a \ \ circle = \frac{22}{7} × 441 m²Area of a circle=
7
22
×441m²
▪︎Area \ \ of \ \ a \ \ circle = \frac{9,702}{7} m²Area of a circle=
7
9,702
m²
☆ After doing division~
▪︎Area \ \ of \ \ a \ \ circle = 1,386 m²Area of a circle=1,386m²
\huge\pink{Area = 1,386 m²}Area=1,386m²
Answer:-
Hence, the area of a circle = 1,386 m².
:)