The common difference is 8 because you add 8 to each number to get to the next number.
To calculate for the perimeter of the garden, we have to solve for the measures of each of the sides of the four-sided polygon. That is calculated by getting the distances between consecutive points.
The equation for the distance is,
d = sqrt ((x₂ - x₁)² + (y₂ - y₁)²)
Distance from G and A,
d = sqrt ((4 - -8)² + (8 - 3)²)
d = 13
Distance from A to R,
d = sqrt ((10 - 4)² + (0 - 8)²)
d = 10
Distance from R to D,
d = sqrt ((-2 - 10)² + (-5 - 0)²
d = 13
Distance from D to G,
d = sqrt ((-8 --2)² + (-5 -3)²)
d = 10
Summing up all the four calculated distances will give us an answer of 46. Thus, the perimeter of the garden is 46 units.
I just convert it to feet which equals to 7920 and then I divided it by 75 minutes and then I got 105.6. I now multiply that by 38 minutes which equals to 4012.8 feet. Then I just convert it back to miles and I got 0.76 miles. Hope it helps