Question

If the cube shown is 7 centimeters on all sides what is the length of the diagonal x.

Answer 1

Answer:

9.899

Step-by-step explanation:

7²+7²=98

$\sqrt{98} =9.899$

Answer 2

There's no cube shown but we can guess the diagonal is the long diagonal.  

In a rectangular parallelpiped (aka a box) with dimensions a × b × c the long diagonal x satifies a 3D version of the Pythagorean Theorem,

x² = a² + b² + c²

In a cube a=b=c

x² = 3a²

x = a√3

Answer: 7√3