15 arches decreased by 80%

If it decreases by 80٪, then only 20٪ remains.

15×20٪=15×20/100=15×0.2=3

3

3 arches

Step-by-step explanation:

Given

15 arches decreased by 80%.

First get 80% of 15 arches

That’s 80%/100% x 15

0.8 x 15

12 arches

Now subtract 12 arches from 15 arches to get the decrease

Decrease = (15 - 12) arches

= 3 arches

Therefore, 80% decrease of 15 inches is equal to 3 arches

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have

the area of the rectangle is 35units^2.

step-by-step explanation:

graph it and find the distance.

it is a 5*7 rectangle.

therefore the area is 35units^2.