Describe the error in the work shown below.
18 + 30 = 6(3 + 10)

18+30 = 48

6(3+10) = 78

so they're not equal

Step-by-step explanation:

to be equal we have to change 6(3+10) to 6(3+5)

18+30 = 48

6(3+5) = 48

now they're equal

25/4

step-by-step explanation:

call segment cd's length x. because dc and ab are parallel, angle acd and cab, so triangles adc and abc are similar and we can set up the equation x / ac = ac / ab, or x / 5 = 5 / 4 and x = 25/4.