1. F
F 3 .3

2. = 1 ×
2 ×
3
_
× ( F )2
F F = 4
= s(s − a )(s − b )(s − c )
a s= a+b+c
b 2
c

3. = F × F
F = กF ×
= 1× ก F F ×
2
F = ×
=1 ×
2 F × ก F ก

4. F = กF x
= F x F
= 1 ×(
2 ก F F )×
F = x
= + F

5. = x
F = (ก F x )x
= ( F x F )x
3
F F = x( F )2 x
4
ก กF F

6. = ( 1×
2 ก F F × )x

7. F F Fก
ก =
2
F ก = 2πr
ก = πr2
F π 1. F F F 22
7
2. F 3.14

8. F ก ก = 2πrh
ก ก( F ) = πr2
ก ก = 2πrh + 2(πr2)
ก ก = πr2h
h
r
r
h ก ก

9. r
h
R
ก กก = πR2h - πr2h
ก กก = πh (R2 - r2)

10. = F x F
F =กF x
= 1 ×
2 ×

11. F = F x (½x F x )
F =½x x
F = ×
2

12. = + F
= +( × )
2

13. = 1 ×
3 ×

14. l h
r
2
l = h2 + r2
F ก = πr l
ก = πr2
ก = πr l + πr2

15. ก = 1 πr2h
3
r
h

16. ก = 4πr2

17. ก = 4 πr3
3