tolong bantu dengan cara

1) sudut B + sudut O = 180
B + 80 = 180
B = 100

2) 150/360 x 2 x 22/7 x 21
= 5/12 x 2 x 22 x 3
= 55

3)Huruf2 nya kurang jelas

4) a. 12 x 7,5 = 90
b. 12 x 8 = 96
c. 12 x 25 = 300

5) L. balok = 2(pl + pt + lt)
= 2(150 + 105 + 70)
= 325 x 2
= 650
Banyak kawat = (650:80) x 5
= 8,125 x 5
= 40,625
Biaya = 40,625 x 2000
= 81.250

6) a. misal p=4x, l=2x, t=3x
L = 2(pl + pt + lt)
1.300 = 2(8x^2 + 12x^2 + 6x^2)
1.300 = 2(26x^2)
1.300 = 52x^2
x^2 = 25
x = 5
jadi p=20, l=10, t=15

b. V = p x l x t
= 20 x 10 x 15
= 3.000