tolong bantu jawab no 3 dan 4 pake cara ok tq makasih

3. tp = tinggi pohon = 12 m
tb = tinggi tiang bendera = 8 m
bb = bayangan tiang bendera = 6 m
bp = bayangan pohon = ? m

tp/tb = bp/bb
12/8 = bp/6
8bp = 12 × 6
8bp = 72
bp = 72 : 8
bp = 9 m

4. d = 14 cm
t = 10 cm
r = 1/2 × d
r = 1/2 × 14 cm
r = 7 cm

V = π × r² × t
V = 22/7 × 7² × 10 
V = 1540 cm³