Respuesta :

Answer:

7 x 21

Step-by-step explanation:

We can say that the dimensions are a and b. Since this is a rectangle, we know that the perimeter will be 2a + 2b. So our first equation is:

2a + 2b = 56.

They also tell us that the length is 3 times its width. So we can say this:

a = 3b.

Now we can substitute, and we can do the full problem with the given info:

2a + 2b = 56

a = 3b

2a = 6b

6b + 2b = 56

8b = 56

b = 7

Now that we know b, we can multiply it by 3 to get a:

b = 7

a = 3b

a = 21.

So our answer is:

a = 21

b = 7

Answer:

Dimensions:

7 x 21

Answer:

Width=7

Length=21

Step-by-step explanation:

p=56 feet

L=3W

P=2L + 2W

56=2(3W)+2W

56=6W+2W

56=8W

W=56/8 = 7 ⇒ Width=7

L=3W

L=3*7

L=21 feet ( length=21 feet)

check : p=2l+2w

P=2(21)+2(7)

p=42+14=56