If the perimeter and the area of a circle are numerically equal, then the radius ofthe circle is:(1) 2 units (l) 4 units(1) munits (iv) 7 units About the author Valentina
Given :- Perimeter of the circle is equal to the area of the circle Aim :- To find the radius of the circle. Formula to use :- Circumference/Perimeter of the circle = [tex]2\pi r[/tex] Area of the circle = [tex]\pi r^{2}[/tex] r represents radius. According to the question, Circumference of the circle = Area of the circle [tex]2\pi r = \pi r^{2}[/tex] By transposing [tex]\pi r[/tex] to the RHS (Right hand side) of the equation, [tex]2 = \dfrac{\pi r^{2} }{\pi r}[/tex] [tex]2 = \dfrac{\pi \times r \times r}{\pi \times r}[/tex] Cancelling the common terms, we get [tex]2 = r[/tex] Hence the radius of the circle will be 2 units. (option 1) Verification :- Let us substitute r to be 2 and verify if the area and perimeter are equal. Area :- [tex]\pi r^{2}[/tex] => [tex]\pi \times (2)^{2}[/tex] => [tex]\pi \times 4[/tex] => [tex]4\pi[/tex] Perimeter/Circumference :- [tex]2\pi r[/tex] => [tex]2 \times \pi \times 2[/tex] => [tex]\pi \times 4[/tex] => [tex]4\pi[/tex] Therefore, Area of the circle = Perimeter of the circle Hence verified. Radius = 2units (option 1) Reply
Given :-
Aim :-
Formula to use :-
Circumference/Perimeter of the circle = [tex]2\pi r[/tex]
Area of the circle = [tex]\pi r^{2}[/tex]
According to the question,
Circumference of the circle = Area of the circle
[tex]2\pi r = \pi r^{2}[/tex]
By transposing [tex]\pi r[/tex] to the RHS (Right hand side) of the equation,
[tex]2 = \dfrac{\pi r^{2} }{\pi r}[/tex]
[tex]2 = \dfrac{\pi \times r \times r}{\pi \times r}[/tex]
Cancelling the common terms, we get
[tex]2 = r[/tex]
Hence the radius of the circle will be 2 units. (option 1)
Verification :-
Let us substitute r to be 2 and verify if the area and perimeter are equal.
Area :-
[tex]\pi r^{2}[/tex]
=> [tex]\pi \times (2)^{2}[/tex]
=> [tex]\pi \times 4[/tex]
=> [tex]4\pi[/tex]
Perimeter/Circumference :-
[tex]2\pi r[/tex]
=> [tex]2 \times \pi \times 2[/tex]
=> [tex]\pi \times 4[/tex]
=> [tex]4\pi[/tex]
Therefore,
Area of the circle = Perimeter of the circle
Hence verified.
Radius = 2units (option 1)
Answer:
1) 2 units
Step-by-step explanation: