When two lines meet or cross that is call intersecting
Step-by-step explanation:

P=2l+2w
W=7+3l
So substitute into the original equation
P=2l + 2(7+3l)
78=2l +14 + 6l
-14 -14
—————-
64=8l
8=length
W=7+3l
= 7+3(8)
=7+24
=31
Check your work
Perimeter=8+8+31+31
=78
Hope this helps
. Perimeter of regular polygons, however, is a required topic. Area (regular polygon) Regular polygons have all sides of equal length. a = apothem p = perimeter