Tolong yaa kak,,no 11 dan 12 pake caranya..!!

[tex]11.\pi \times 7 \times 7 \\ \frac{22}{7} \times 7 \times 7 = 154 \\ \frac{1}{2} \times 14 \times 14 \times \frac{22}{7 } = 308 \\ 154 + 308 = 462[/tex]
[tex]12. a.\frac{1}{2} \times 3.14 \times 10\times 10= 157 \\b. 10 \times \frac{1}{2} \times 8 = 40 \\ c.20 \times 20 = 400 \\ 400 - 40 - 157 = 203[/tex]