The answer is 3 8/9 because you turn it into a mixed number which is 5/3*7/3. Once you multiply you get 35/9. Since it is an improper fraction you turn it into a mixed number by dividing 35/9. In the end, you get 3 8/9 as your final answer.
Multiply each number. Remember that when multiplying a negative and positive number, the outcome will be negative
7 x -5 = -35
-35 x 4 = -140
-140 is your answer
hope this helps
The area <em>A</em> of a trapezoid with height <em>h</em> and bases <em>b</em>₁ and <em>b</em>₂ is equal to the average of the bases times the height:
<em>A</em> = (<em>b</em>₁ + <em>b</em>₂) <em>h</em> / 2
We're given <em>A</em> = 864, <em>h</em> = 24, and one of the bases has length 30, so
864 = (<em>b</em>₁ + 30) 24 / 2
864 = (<em>b</em>₁ + 30) 12
864 = (<em>b</em>₁ + 30) 12
72 = <em>b</em>₁ + 30
<em>b</em>₁ = 42
The perimeter is 17 units! :D