Answer:
21.98in²
Explanation:
The section of the birthday pie that Karen ate forms a sector.
The central angle of this sector is 70°
The diameter is 12 inches.
This means the radius which is half of the diameter is 6 inches.
The area of the section that is leftover is given by:
![= ( \theta)/(360 \degree) * \pi \: {r}^(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/7l7r03etgmqvz2lobazo4qeiu6tdsxnb8m.png)
We substitute to get:
![= (70)/(360) * 3.14 * {6}^(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5sf0mmgpv3j8vbetayvczb9z46fwcrpd6b.png)
![= (7)/(36) * 3.14 * 36 = 7 * 3.14 \\ = 21.98 {in}^(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/twzdu7juf5sd5oamlw3bjsrg0t6rrsec5z.png)