Answer
(a+b)(c+d) = ac+bc+ad+bd
Work Step by Step
Given The algebra method of FOIL multiplication is illustrated
geometrically in the drawing. Use the drawing with
rectangular regions to complete the following rule:
(a+b)(c+d) = -------
We know area of rectangle A = b* h
The given drawing consist of 4 rectangles
The area of sum of all rectangles = (a+b)(c+d)
Lets find the area of all the 4 rectangles separately
Rectangle I = ac
Rectange II = bc
Rectangle III = ad
Rectangle IV = bd
The total area of big rectangle = Area of I + Area of II = Area of III + Area of IV
= ac+bc+ad+bd
=c(a+b)+d(a+b)
=(c+d)(a+b)
