Explicație pas cu pas:
1.a)A____10___B_____42_________C
b)A______45______C____19____B. AB=64
c)B__16____A______38_____C. BC=54
2.AB=12×2=24m
DC=7×2=14m
AD=BC=2/3AB=(24:3)×2=16m
gardul=AB+BC+CD+CA=24+16+14+16=70m
3,A______R_______P______Q______B
AP=PB
AR=1/4dinAB AB =20
PQ=QB
segmentul AB se împarte în 4 =>20:4=5
a)AP=10cm b)PQ=5cm c)RQ=10cm
4.(a+b+c)/3=2,8
a+b+c=2,8×3
(a+b+c+d)/4=2,8-0,4
(2,8×3+d)/4=2,4
(8,4+d)=2,4×4
8,4+d=9,6
d=9,6-8,4=1,2 d=1,2
5.1/2drum-5km=0,3drum
D/2-5=D×0,3
D(0,5-0,3)=5
D=5:0,2=5:2/10=5×10:2=25km
/________/________/
/________/-5km
