Solution
Step 1
State the number of shapes in the figure
The shape is made up of
2 triangles
and
3 rectangles
Step 2
State an expression for the area of a triangle and find the area of the triangle
[tex]\text{The area of a triangle ( A}_1)\text{ = }\frac{1}{2}\times base\text{ }\times height[/tex]Where the base = 10cm
height = 4cm
The area of the triangle after substitution is
[tex]\begin{gathered} A_1=\frac{1}{2}\times10\times4 \\ A_1=20cm^2 \end{gathered}[/tex]Since there are two triangles total area of the triangles = 2 x 20 = 40cm²
Step 3
State the expression for the area of a rectangle
[tex]\text{Area of a rectangle = Length }\times width_{}[/tex]Where
For rectangle 1
length = 8cm
width = 9cm
Area of rectangle 1 after substitution = 8 x 9 = 72cm²
For rectangle 2
length = 10cm
width= 9cm
Area of rectangle 2 after substitution = 9 x 10 = 90cm²
For rectangle 3
length = 5cm
wiidth = 9cm
Area of rectangle 3 after substitution = 9 x 5 = 45cm²
Step 4
Find the total area of the shape
[tex]\text{Total surface area of the shape = 45 +90 +}72+40=247cm^2[/tex]Therefore the surface area of the shape = 247cm²
