Question

Use cross products to determine whether the proportion below is true or false.420459Is the proportion true or false?A. False. The numerators of the two ratios are not equal.B. False. The denominators of the two ratios are not equal.O C. False. The cross products are not equal.O D. True. The cross products are equal.ba

Answer 1

Cross product

We want to find the cross product of:

`(4)/(9)\text{ and }(20)/(45)`

Then, we have a kind of X:

We multiply the numbers inside the red oval:

4 x 45 = 180

and the blue oval

9 x 20 = 180

Then, the cross products are equal and the proportion

`(4)/(9)=(20)/(45)\text{ is true}`

Answer: D. The cross products are equal