Question

What is the length of side BD?

Answer 1

I would say the length of side BD is 26.1 rounded to the tenths place.
Explanation:
You can use Cosine
Equation: Cos(40)=20/x [x being BD]
Or 20/Cos(40) which leaves you with 26.10815...
Therefore BD’s length would be 26.1 when rounded.

Answer 2

Answer:  26.1

Step-by-step explanation:

$cos\theta=\dfrac{adjacent}{hypotenuse}\\\\\\cos(40^o)=\dfrac{20}{BD}\\\\\\BD=\dfrac{20}{cos(40^o)}\\\\\\BD=26.1$