You might want to first slice the shape into two rectangles.
Rectangle #1
3cm by 5cm
Rectangle #2
7cm by 8cm
Find the area of both recrangles separately.
Rectangle 1 area
3×5= 15 cm squared
Rectangle 2 area
7×8= 56 cm squared
Then just add the two areas together to fnd the total area.
Answer
15cm + 56cm = 71 cm squared.
*area of recangle is found by multiplying Length times Width