Answer:
Therefore,
The lengths of side a and b are,

Explanation:
Given:
Shape is of triangular prism.
Length = a
Width = b
Height = h =10 mm
Also, b = 2a
Volume of the Triangular Prism = 40 mm³
To Find:
a = ?
b =?
Solution:
Shape is of triangular prism. GIVEN
We Know that,
Substituting the given values we get

But ,
Given
Substituting a we get
Therefore,
The lengths of side a and b are,
