Tolong bantu jawab Nomor 12 sampai 16 . thank youu..

12.)
40 = 28
30 = x

30/40 = x/28
x = 28 × 30/40
x = 21cm

13.) Luas juring =
3,14 × 10 × 10 × 1/4 =
314/4 = 78,5cm^2

Luas segitiga = 10 × 10/ 2 = 50cm^2

Luas yang diarsir = 78,5 - 50 = 28,5

14.)
180 - (180 - 52 - 30) =
180 - 98 =
82 derajat

X + 40 + 2x - 25 = 180
3x = 180 - 15
x = 165/3 = 55

3y + 90 = 180
3y = 180 - 90
y = 90/3 = 30

Nilai x + y = 55 + 30 = 85