Zad. 27.
a) [tex]P=\frac{(8+12)*4}{2} = (8+12)*2 = 20*2=40cm^{2}[/tex]
b) [tex]P = \frac{(9+14)*7}{2} = \frac{161}{2} = 80,5cm^{2}[/tex]
c) [tex]P = \frac{(7+3)*10}{2} =(7+3)*5=10*5=50cm^{2}[/tex]
Zad. 29.
a) a = 71 cm = 7,1 dm
b = 5,7 cm
h = 1,5
[tex]P = \frac{(5,7 + 7,1)*1,5}{2} = \frac{12,8*1,5}{2} =\frac{19,2}{2} = 9,6 dm^{2}[/tex]
b) a = 11,5 + 4,2 + 5,3 = 21 dm
b = 11,5 dm
h = 14 dm
[tex]P=\frac{(21+11,5)*14}{2} = \frac{32,5*14}{2} = \frac{455}{2} = 227,5 dm^{2}[/tex]
c) a = 15 + 2 - 5 = 12 cm
b = 15 cm
h = 7 cm
[tex]P = \frac{(12+15)*7}{2} = \frac{27*7}{2} = \frac{189}{2} = 94,5 cm^{2}[/tex]
Zad. 30.
a) [tex]P1 = \frac{(7,5+19)*5}{2} =\frac{26,5*5}{2} = \frac{132,5}{2} = 66,25 dm^{2}[/tex]
[tex]P2 = 19 * 7 = 133dm^{2}[/tex]
[tex]P = 66,25 + 133 = 199,25 dm^{2}[/tex]
b) [tex]P1 = \frac{(6,5+4)*3}{2} = \frac{10,5*3}{2} = \frac{31,5}{2} = 15,75 dm^{2}[/tex]
[tex]P2 = 3 * 8,5 = 25,5 dm^{2}[/tex]
[tex]P = 15,75 + 25,5 = 41,25dm^{2}[/tex]
c) [tex]P1 = \frac{(4+7)*4}{2} = \frac{11*4}{2} = \frac{44}{2} = 22 dm^{2}[/tex]
[tex]P2 = \frac{7*4}{2} = \frac{28}{2} = 14dm^{2}[/tex]
[tex]P = 22 + 14 = 36dm^{2}[/tex]
d) [tex]P1 = \frac{(5+6)*2}{2} = 5+6=11dm^{2}[/tex]
[tex]P2=\frac{(10+21)*2}{2} = 10 + 21 = 31dm^{2}[/tex]
[tex]P3=\frac{(27+30)*6}{2} = (27+30) * 3= 57 * 3=171dm^{2}[/tex]
[tex]P = 11 + 31 + 171 =213dm^{2}[/tex]
e) [tex]P1 = \frac{2*2}{2} = 2dm^{2}[/tex]
[tex]P2 = 10 * 6 = 60 dm^{2}[/tex]
[tex]P = 10 * 2 + 60 = 20 + 60 = 80 dm^{2}[/tex]
Zad. 31.
a) a = 14 cm
b = 14 - 3 = 11 cm
h = 18 cm
[tex]P = \frac{(14+11)*18}{2} = (14+11)*9=25*9=225cm^{2}[/tex]
b) P = 115 cm²
a = 10 cm
b = 13 cm
[tex]P = \frac{(a+b)*h}{2} /*2[/tex]
[tex]2P = (a + b)*h /:(a+b)[/tex]
[tex]h = \frac{2P}{a+b}[/tex]
[tex]h = \frac{2*115}{10+13} = \frac{230}{23} = 10 cm[/tex]
Sorry, ale za mało punktów na rozwiązanie wszystkich zadań :/ i tak długo mi to zeszło
