tolong dong 7 sama 12

7.
a. L = d1 × d2 ÷ 2
108 = (a + 2) × 18 ÷ 2
108 = (a+2) 9
108/9 = a + 2
12 = a + 2
12-2 = a
10 = a

b. Diagonal yg lain = a + 2 = 10 + 2 = 12 cm


12.
a. L = a×t
L = DC × t
L = 6 × 3
L = 18

b. L = AD × t
18 = 4 × t
18/4 = t
4,5 = t