The perimeter of the envelop is 30 in.
Explanation:
Given,
The length (l) of the envelop = 7 inches
Width (b) of the envelop = 8 inches
To find the perimeter of the envelop.
Formula
The perimeter of a rectangle = 2(l+b)
So,
The perimeter of the envelop = 2(7+8) in
= 30 in