tolong yaa pakai cara

Bab Bangun Datar

a = 4y
t = 5y

L = 1/2 × a × t
90 × 2 = 4y × 5y
20y² = 180
y² = 9
y = √9
y = 3

t = 5y
t = 5(3)
t = 15 cm