Well, you could tackle the rectangle first; it doesn't really matter what order you go in, as long as you get the final answer.
1) I'll start with the rectangle. Area=base x height, so 10*4=40
2) The top triangle will go next. Area=(base x height) divided by two. 4*10=40
40/2=20
3) Bottom triangle. 3*10=30
30/2=15
4) Add all areas together: 40+20+15=75
The total area is 75cm².
Hope this helps!
