Jasmine the Great Dane has a head 30 cm long. Her tall is equal to the size of her head plus one-half the size of her body. Her body is the size of her head phluss the tal. How long is Jasmine? ​

240 cm

Step-by-step explanation:

Let x = tail   y = body

x = 30 + 1/2y

y = 30 + x

Let's plug in the x equation at the bottom

y = 30 + 30 + 1/2y

y = 60 + 1/2y

Bring the like terms to one side

y = 60 + 1/2y

-1/2y    -1/2y

1/2y = 60

Multiply both sides by 2 to get the length of the body

1/2y x 2 = 60 x 2

y = 120

Now we can plug in the new y into another equation, let's use the top one

x = 30 + 1/2(120)

x = 30 + 60

x = 90 = length of the tail

Add em all up

120 + 90 + 30 = 240

I'll explain by using an example first.
Let's say that you are given the area of a square is 64 square meters. You find the area of a square by multiplying the base and height or just side². Therefore, you find the length of one side by square rooting the 64, which equals 8. Because you know there are 4 congruent sides in a square, the perimeter is 4×8 = 32 meters.

Step 1: take the square root of the given area to find length of one side
Step 2: multiply the square root by 4 to get perimeter