Jawablah pertanyaan pada gambar diatas​

Nomer 1

y – x + 60 = 180
y – x = 20
y = 20 + x

x + 2y + 20 + 90 = 180
x + 2y + 110 = 180
x + 2y = 70

substitusikan
x + 2y = 70
x + 2(20 + x) = 70
x + 40 + 2x = 70
3x + 40 = 70
3x = 30
x = 10

maka nilai y
y = 20 + x
y = 20 + 10
y = 30

nomer 2
.luas
= 1/2 . d1 . d2
= 1/2 . 20 .32
= 320 cm²

keliling
= (2 x 30) + (2 x 15)
= 60 + 30
= 90 cm