Tolong bantu jawab no 3 sma 4 donk

3.
DE / AB = CE / CB
DE / 4 = 3 / 5
DE = 3/5 x 4
DE = 12/5
DE = 2,4 cm

Luas CDE = 1/2 x DE x CE
L = 1/2 x 2,4 x 3
L = 3,6 cm²

4.
BE = AB = 4 cm
FB = CF = 3 cm

FE² = BE² + FB²
FE² = 4² + 3²
FE² = 16 + 9
FE² = 25
FE = √25
FE = 5 cm

Keliling = BE + FE + FB = 4 + 5 + 3 = 12 cm