Total surface area of a hemisphere is equal to the surface of a sphere, then the ratio of their radii is ?
Answers
Answer:
2 : √3
Step-by-step explanation:
Using the basic properties of 2D figures.
Total surface area of hemisphere is 3πr²
And, surface area of sphere is 4πr².
Let the radius of hemisphere be r and radius of sphere be R.
So, according to question,
= > total surface area of hemisphere = surface area of sphere
= > 3πr² = 4πR²
= > 3r² = 4R²
= > r²/R² = 4/3
= > r / R = √(4/3)
= > r / R = 2/√3
= > r / R = 2/√3 = > r : R = 2 : √3
Answer:
ratio 3:4
Step-by-step explanation:
The surface area of the sphere is 4πr2
The surface area of the hemisphere is equal to sum of the “curved” and “flat” areas (the curved area being half the surface area of the sphere, and the flat area of the sphere being equal to the area of a circle with radius r . The total area, then, is equal to 2πr2 + πr2 = 3πr2 .
The ratio, therefore, is 3:4.