Answer:
x = 6
Step-by-step explanation:
The scale factor is
28/8 = 7/2
We take the ratio of the larger side over the smaller side
Using ratios we can find the sides
28 21
----- = ---------
8 x
Using cross products
28x = 21*8
28x =168
Divide each side by 28
28x/28 = 168/28
x =6
