Question

What is diameterof the circle if the area of the circle is78.5cm

Answer 1

Given :-

• Area of circle = 78.5 cm²

To Find :-

• The diameter of circle = ?

Answer :-

• The diameter of circle = 10 cm

Explaination :-

• Let 'r' be the radius of the Circle.

★ According to Question :-

→ Area of circle = πr²

• Taking π = 3.14 we get :

→ 78.5 = 3.14 × r²

→ r² = 78.5 ÷ 3.14

→ r² = 25

Taking square root to the both sides we get :

→ r = √25

→ r = 5 cm

Now,

As we know that,

→ Diameter = 2 × Radius

Substituting the value of r in above formula :

→ Diameter = 2 × 5

→ Diameter = 10 cm

Hence,

• The diameter of circle is 10 cm.

__________________

Extra Shots :-

• Volume of cylinder = πr²h
• T.S.A of cylinder = 2πrh + 2πr²
• Volume of cone = ⅓ πr²h
• C.S.A of cone = πrl
• T.S.A of cone = πrl + πr²
• Volume of cuboid = l × b × h
• C.S.A of cuboid = 2(l + b)h
• T.S.A of cuboid = 2(lb + bh + lh)
• C.S.A of cube = 4a²
• T.S.A of cube = 6a²
• Volume of cube = a³
• Volume of sphere = 4/3πr³
• Surface area of sphere = 4πr²
• Volume of hemisphere = ⅔ πr³
• C.S.A of hemisphere = 2πr²
• T.S.A of hemisphere = 3πr²