3-
[tex]((11 + 19) \times 10) \div 2 \\ = (30 \times 10) \div 2 = 300 \div 2 = 150[/tex]the answer is 150 units^2
4- the area of the rectangle:
[tex]14 \times 21 = 294[/tex]
the area of the triangle :
[tex](16 \times(21 - 12)) \div 2 = \\ (16 \times 9) \div 2 = 144 \div 2 = 72[/tex]
the area of the whole shape:
[tex]294+ 72 = 366[/tex]
the answer is 366 units^2
hope this helps
