Question

Kto pomoże zad.5.15 bardzo proszę. Daje naj

Answer 1

Odpowiedź:

Proszę bardzo! :D

Zad. 5.15.

a)

Pp = a * b = 7,2 cm * 4 cm = 28,8 cm^2

V = 1/3 * h * a*b = 1/3 * 4,8 cm * 28,8  cm^2 = 1,6 * 28,8 = 46,08 cm^3

1/2b =  4/2 = 2 cm

1/2a = 7,2/2 = 3,6 cm

L1^2 = 2^2 + 4,8^2

L1^2 = 4 + 23,04 = 27,04

L1 =   = 5,2 cm

L2^2 = 4,8^2 + 3,6^2

L2^2 = 23,04 + 12,96 = 36

L2 = = 6 cm

Pc = 28,8 + 2 * (0,5 * 4,8 * 5,2) + 2 * (0.5 * 4,8 * 6) = 28,8 + 24,96 + 28,8 = 82,56 cm^2

b)

c^2 = a^2 + b^2 = 12^2 + 5^2 = 144 + 25 = 169

c = = 13 cm

Pp = 0,5 * 12 * 5 = 30 cm^2

V = 1/3 * 30 * 144/13 = 10 * 144/13 = 1440/13 = 110 i 10/13 cm^3

Pp = 0,5 * c * h = 30 cm^2

0,5 * 13 * h = 30

6,5h = 30    /6,5

h = 60/13 cm

L^2 =  (144/13) ^2   + (60/13) ^2 = 20736/169  + 3600/169 = 24336/169 = 144 cm

Pc = 30 cm^2 + (0,5 *12 * 144/13) cm^2 + (0,5 * 5 * 144/13) cm^2 = 30 + 864/13 + 360/13 = 30 + 1224/13 = 30 + 94 i 2/13 = 124 i 2/13 cm^2

C)

Pp = 0.5 * 80 * 60 = 2400 cm^2

V = 1/3 * 57,6 cm * 2400 cm^2 = 57,6 * 800 = 46080 cm^3

1/2d1 = 40 cm

1/2d2 = 30 cm

a^2 = 40^2 + 30^2 = 2500

a = = 50 cm

a/2 = 25 cm

1/2d2^2 = 25^2 + x^2

30^2 = 25^2 + x^2

900 = 625 + x^2

x^2 = 900 - 625 = 275

x =

L^2 = 57,6^2 +( )^2 = 3317,76 + 275 = 89819/25

L = = 59,939 cm = 60 cm

Pc = 2400 cm^2 + 4 * (0.5 * 60 * 50) cm^2 = 2400 + 6000 = 8400 cm^2