To find the length of $BD$ given that $BC = 17$ and $CD = 18$, we assume that points $B$, $C$, and $D$ are collinear. This implies that $BD$ is the sum of $BC$ and $CD$.

Thus,

$BD = BC + CD = 17 + 18 = 35$

So, $BD = 35$.

Would you like further details or have any questions?

Here are 5 related questions:

1. If $BC = 17$ and $BD = 35$, what is $CD$?
2. If $BD = 35$ and $CD = 18$, what is $BC$?
3. If $BC = 17$ and $BD = 35$, what is the midpoint of $BD$?
4. If $BC = 17$ and $CD = 18$, how would the length of $BD$ change if $BC$ is doubled?
5. How do you calculate $BD$ if $BC$ and $CD$ are perpendicular rather than collinear?

Tip: Always check whether points are collinear when summing segment lengths.