The formula of an area of trapezoid:
[tex]A=\dfrac{base_1+base_2}{2}\cdot height[/tex]
We have:
[tex]base_1=3ft+4ft=7ft\\\\base_2=3ft\\\\height=3ft[/tex]
Substitute:
[tex]A=\dfrac{7+3}{2}\cdot3=\dfrac{10}{2}\cdot3=5\cdot3=15\ ft^2[/tex]
The perimeter:
[tex]P=3+4+5+3+3=18\ ft[/tex]
