Question

1. a. about what percent of earths atmosphere consists of oxygen? round to the nearest ten percent. b. write the answer to a as a reduced fraction.

Explanation:

Step1: Recall the percentage of oxygen in Earth's atmosphere

The approximate percentage of oxygen in Earth's atmosphere is \(21\%\). Rounding \(21\%\) to the nearest ten percent: \(21\) is closer to \(20\) than to \(30\).

Step2: Convert the percentage to a fraction

To convert \(20\%\) to a fraction, we know that \(20\%=\frac{20}{100}\). Simplify \(\frac{20}{100}\) by dividing both the numerator and the denominator by their greatest - common divisor. The GCD of \(20\) and \(100\) is \(20\). So \(\frac{20\div20}{100\div20}=\frac{1}{5}\).

Answer:

a. \(20\%\)
b. \(\frac{1}{5}\)