tolong jawab no 3-5 pakai cara y kaka

L=1/2(a+c)×t

3) b=8m t=7m L=84m persegi
L=1/2(a+b)×t
84=1/2(a+8)×7
84=7/2×(a+8)
(a+8)=84:7/2 = 84×2/7 =24
a=24-8=16cm

4) a=24m t=9m L=162m persegi
L=1/2(a+b)×t
162=1/2(24+b)×9
162=9/2×(24+b)
(24+b)=162:9/2 =162×2/9 =36
b=36-24=12cm

5) a=30m b=16m L=253m persegi
L=1/2(a+b)×t
253=1/2(30+16)×t
253=1/2×46×t
253=23×t
t=253:23=11m