Answer
4,10
Work Step by Step
Here, we do not know the measure of angle B. While we know the length of the side CB, there are two options: B could be acute or obtuse. This will result in two different lengths for side DC. We draw a vertical line between point C and line segment AB to create a triangle for the acute angle. The base of this triangle will b:
$$ =\sqrt{5^2-4^2} \\ =3$$
Thus, the length of DC is:
$$ 7 \pm 3$$
So, the two possible lengths are:
$$\fbox{4,10}$$
