Face Diagonal and Space Diagonal of a Rectangular Prism

Face diagonal and space diagonal of a cube 

Ways to calculate face and space diagonal.

Each side of the cube is x units long.

Use  45-45-90 degree angle ratio
( 1 - 1 - √ 2  ) or Pythagorean theorem to get the face diagonal.

Using Pythagorean theorem twice and you'll get the space diagonal.







Face diagonal and Space diagonal of a rectangular prism.

Same way to figure out the face

diagonal of a rectangle as well as

space diagonal of a rectangular prism.

Use Pythagorean theorem or

30-60-90 degree angle ratio

(1 -√ 3  - 2) to figure out the face

diagonal and Pythagorean theorem

twice to figure out the space diagonal.