Table of Contents

Last modified on August 3rd, 2023

The diameter of a cone is the diameter of its circular base. It is the distance between any 2 points on the circumference of the base passing through the center. It is denoted by d.

Like radius, it is expressed in mm, cm, m, in, ft, and yd.

The formula to calculate the diameter of a cone can be obtained from the formula used to calculate the volume of a cone.

As we know,

**Volume** ${\left( V\right) =\dfrac{1}{12}\pi d^{2}h}$, here d = diameter, h = height, π = 3.141

Therefore, by rearranging the equation, we can write the formula of diameter as:

${d=2\sqrt{\dfrac{3V}{\pi h}}}$

**Find the diameter of a cone with a volume of 667 cm ^{3} and a height of 13 cm.**

Solution:

As we know,

${d=2\sqrt{\dfrac{3V}{\pi h}}}$, here V = 667 cm^{3}, h = 13 cm, π = 3.141

${\therefore d=2\times \sqrt{\dfrac{3\times 667}{3\cdot 141\times 13}}}$

= 14 cm

Finding the **DIAMETER** of a cone with **SLANT HEIGHT** and **HEIGHT**

**Calculate the diameter of a right circular cone with a slant height of 16 mm and a height of 12 mm.**

Solution:

Here we will apply the Pythagorean Theorem considering the slant height as hypotenuse and height as the perpendicular leg and find the diameter as the base of a right triangle.

${d=2\sqrt{s^{2}-h^{2}}}$, here s = 16 mm, h = 12 mm, π = 3.141

${\therefore d=2\sqrt{16^{2}-12^{2}}}$

= 21.16 mm

Finding the **DIAMETER** of a cone with **SLANT HEIGHT** and **LATERAL SURFACE AREA**

**Calculate the diameter of a cone with a slant height of 6.5 cm and a lateral surface area of 225 cm ^{2}.**

Solution:

As we know,

r = d/2, we will replace this in the equation of Lateral Surface Area (LSA):

${\because LSA=\pi \dfrac{d}{2}s}$

Rearranging the equation to find d:

${d=2\dfrac{LSA}{\pi s}}$, here LSA = 225cm^{2}, s = 6.5cm, π = 3.141

${\therefore d=\dfrac{2\times 225}{3.141\times 6\cdot 5}}$

= 22.04 cm

Last modified on August 3rd, 2023