Answer:
Here's how I would do it.
Step-by-step explanation:
If two triangles are similar, corresponding sides are in the same ratio.
We know the measures of b and a, so we can calculate the ratio b/a.
d and b are in the same ratio, so
[tex]\begin{array}{rcl}\dfrac{d}{c}& = & \dfrac{b}{a}\\d & = & c \times \dfrac{b}{a}\\\end{array}[/tex]
We know the measures of c, b, and a, so we can calculate the value of d.