Answer:
12. 10.5 cm
13. 16 m
14. 8 m
15. 50.24 m
16. 200.96 m2
17. (16+4 =20 ÷2 =10 ·10·π =314 ÷2 =157) + (16·4 =64) =221 in2
18. (1.1 · 1.2 =1.32) + (1.2 · 4 =4.8 ÷2 =2.4) =3.72 in2
19. 10·5=50
20. c.(1/2 d)^2·π
