3. Write each increase as a percent. Illustrate each answer with a number line. a) The price of a house increased from \( \$ 210000 \) to \( \$ 225000 \). b) The elastic stretched from 10 cm to 13 cm .

To write each increase as a percent, we need to calculate the percentage increase in the price of the house and the length of the elastic. a) Percentage increase in the price of the house: \[ \text{Percentage increase} = \left( \frac{\text{Increase in price}}{\text{Original price}} \right) \times 100 \] Given: Original price = $210,000 Increase in price = $225,000 - $210,000 = $15,000 \[ \text{Percentage increase} = \left( \frac{15000}{210000} \right) \times 100 = 7.14\% \] b) Percentage increase in the length of the elastic: \[ \text{Percentage increase} = \left( \frac{\text{Increase in length}}{\text{Original length}} \right) \times 100 \] Given: Original length = 10 cm Increase in length = 13 cm - 10 cm = 3 cm \[ \text{Percentage increase} = \left( \frac{3}{10} \right) \times 100 = 30\% \]