About \( \frac{39}{50} \) of Earth's atmosphere is made up of nitrogen. Use equivalent ratios to find about what percent of the atmosphere is nitrogen.

To find the percentage of Earth's atmosphere that is made up of nitrogen using equivalent ratios, we can set up a proportion based on the fraction given. 1. We know that \( \frac{39}{50} \) represents the part of the atmosphere that is nitrogen. 2. We want to express this fraction as a percentage, which is a ratio out of 100. We can set up the following proportion: \[ \frac{39}{50} = \frac{x}{100} \] where \( x \) is the percentage of nitrogen in the atmosphere. 3. To solve for \( x \), we can cross-multiply: \[ 39 \cdot 100 = 50 \cdot x \] 4. This simplifies to: \[ 3900 = 50x \] 5. Now, divide both sides by 50 to isolate \( x \): \[ x = \frac{3900}{50} \] Now, let's calculate \( x \). Calculate the value by following steps: - step0: Calculate: \(\frac{3900}{50}\) - step1: Reduce the numbers: \(\frac{78}{1}\) - step2: Calculate: \(78\) Calculating \( x \) gives us: \[ x = \frac{3900}{50} = 78 \] Thus, about \( 78\% \) of Earth's atmosphere is made up of nitrogen.