Question

сар
If the radius of a sphere is doubled, what is the
ratio of the volume of the first sphere to that of
the second sphere?
A hemisphere of lead of radius 7 cm is cast into
a right circular cone of height 49 cm. Find the
radius of the base.
The outer diameter of a spherical shell is 10 cm
and the inner diameter is 9 cm. Find the volume
of the metal contained in the shell.
A cone and a hemisphere have equal bases and
equal volumes. Find the ratio of their heights.​

Answer 1

Step-by-step explanation:

1.

Let the radius of the present sphere be r

and new radius be R

Therefore, volume of present sphere

=4/3 π r^3

and volume of new sphere

=4/3 π R^3

Ratio of their volumes will be

= (4/3 π r^3) / (4/3 π R^3)

r^3 : R^3

2.

radius of hemisphere= 7

volume= 2/3 π r^3

= 2/3 * 22/7 * 7 * 7 * 7

=2156/3

height of cone = 49

since, hemisphere is only casted into cone, their volumes will be equal.

volume of cone = 2156/3

1/3 π r^2 h = 718.67

1/3 * 22/7 * r * r * 49 = 2156/3

r^2 = 14

r = ✓14

Answer 2

Answer:

answer of first Ques:-)