Question

The human eyeball is a sphere with a surface area of 20 square cm. find the approximate radius of the human eyeball.

a. 1.26 cm
b. 1.59 cm
c. 2.24 cm
d. 4.47 cm

Answer 1

a. 1.26 cm

Explanation:

Since, the surface area of a sphere is,

`A=4\pi r^2`

Where, r is the radius of the sphere,

Given,

A = 20 square cm,

`\implies 20 = 4\pi r^2`

`\implies r^2 =(20)/(4\pi)`

`r^2 = (5* 7)/(22)`

`r^2=(35)/(22)`

`r=\sqrt{(35)/(22)}=1.261312447\approx 1.26`

Hence, the radius of the eyeball is 1.26 cm.

Option 'a' is correct.

Answer 2

Surface area of a sphere formula is 4π (radius squared)20 square cm = 4x 3.14 x radius squared
20 square cm=12.56 x radius squared
here we will divide both sides by 12.56 to find radius squared
20/12.56=radius squared
1.5924= radius squared
square root 1.5924=radius
1.26cm=radius of the eye ball
the answer is A. 1.26 cm