Question

The diagram shows a circular cone that has been
filled to a depth of 18 cm. Find the radius r of the top
of the cone.
​

Answer 1

Answer:

58 cm is the answer of diagram

Answer 2

Answer:

8cm

Step-by-step explanation:

This will be solved by similarity. A cone is symmetrical to the straight line from its core that will bisect its face diameter.

So let's say the triangle with sides 12cm and altitude 18cm is similar to the bigger triangle (the cone).

Similar triangles have similar parts' ratio equal.

So base/altitude of smaller triangle would be equal to base/altitude of bigger triangle.

Altitude of bigger triangle is 24 cm (given) and its base is 2r

So 12cm/18cm = 2r/24cm

r= 12cm×24cm/18cm×2

r=8cm

So radius r of top of cone is 8cm