Question

If AD = y + 6 and DC = 2y, what is the length of DC?

Answer 1

We are given
AD = y + 6 and DC = 2y

From the figure, we have the equation
AD = DC
Substituting the given
y + 6 = 2y
Solving for y
y = 6

Subsituting the value of y in DC
DC = 2(6) = 12

Answer 2

`DC=12\ units`

Explanation:

Step 1

Find the value of y

In this problem we know that

`AD=DC` -----> equation A

`ED=DB`

see the attached figure to better understand the problem

so

we have

`AD=y+6`

`DC=2y`

substitute the values in the equation A

`y+6=2y`

solve for y

`2y-y=6`

`y=6\ units`

Step 2

Find the value of DC

we have that

`DC=2y`

substitute the value of y

`DC=2(6)=12\ units`