Answer:
its A.
Step-by-step explanation:
<h2>
Answer:</h2>
This is easy. All you need to do is set up a <u><em>proportional relationship</em></u>.
A proportional relationship uses variables to show similarities, in this case, in triangles.

<u><em>x</em></u> represents the missing side.
<span>The doubling time is the period of time
required for a quantity to double in size or value. It is applied to
population growth, inflation, resource extraction, consumption of goods,
compound interest, the volume of malignant tumours, and many other
things that tend to grow over time.</span>