Question

lesson 1 | session 2
3 the photo shows a small coin. the scale from the actual coin to the photo is
8 mm to 2 cm. in the photo, the distance across the coin is 3.25 cm. what is the
distance across the actual coin? show your work.

Explanation:

Step1: Convert units

Since \(1\ cm = 10\ mm\), then \(8\ mm=0.8\ cm\). Let the actual distance across the coin be \(x\) cm.
The scale ratio is \(\frac{\text{actual}}{\text{photo}}=\frac{0.8}{2}\).

Step2: Set up proportion

We know that \(\frac{x}{3.25}=\frac{0.8}{2}\).
Cross - multiply: \(2x = 0.8\times3.25\).

Step3: Solve for \(x\)

\(2x=2.6\), then \(x=\frac{2.6}{2}=1.3\) cm.
Since \(1\ cm = 10\ mm\), \(1.3\ cm = 13\ mm\).

Answer:

The distance across the actual coin is \(13\) mm.