From the information given,
width of base = 4
length of base = 5
height of wall = 3
a is the slant height of the roof
Let h represent the height of the roof. The triangle formed is shown below
By applying the pythagorean theorem,
a^2 = h^2 + 2^2
a^2 = h^2 + 4
Let the height, h be 1.5 ft
Thus,
a^2 = 1.5^2 + 4 = 6.25
a = √6.25
a = 2.5
The slant height of the roof is 2.5 ft
Area of roof = 2 x slant height x length of base = 2 x 2.5 x 5
Area of roof = 25 square ft
