Radius Find

 Step 1: Set up your units 

1. Open Blender and select the Scene Properties tab (the icon with a cone and sphere) from the Properties Editor.
2. Under the Units section, change the Unit System to Metric.
3. Set the Length to Centimeters. This will allow you to directly enter "cm" values without Blender performing a conversion. 

Step 2: Calculate the radius 

The formula for circumference is

$C=2\times \pi \times r$

, where

$C$

is the circumference and

$r$

is the radius. 

• 

  $C=64\text{cm}$
• 

  $r=\frac{C}{2\times \pi }$
• 

  $r=\frac{64}{2\times \pi }\approx 10.186\text{cm}$

Step 3: Create the cylinder 

1. Delete the default cube by selecting it and pressing the Delete key.
Press Shift+A and navigate to Mesh > Cylinder to add a new cylinder to your scene.A menu will appear in the bottom-left corner of the 3D viewport. If it is hidden, press F9 to open it.In the menu, find the Radius field and enter your calculated value: 10.186 cm.Press Enter to confirm the value and create the cylinder with a 64 cm circumference. You can now adjust the cylinder's height or other properties as needed.