Question

Problema 5 va rog dau Coroana

Answer 1

∆ ABC isocel BC=12cm;AB=AC=10cm

BD=DC=BC/2=12/2=6cm; AE=EC

a)aria ∆ ABC=48cm²

demonstrație

AD _l_BC ; AD=√ AB ²-BD²=√100-36=8cm

aria=BC ×AD/2=12×8/2=48cm²

b) AF ll BC

B; E; F colineare DF n AC=M

DM=?

∆AMF≈∆DMC {AF ll DC;<AMF=<DMC opuse

la vârf}

rapoartele de asemănare sunt

AF/DC=FM/DM

12/6=(FD -DM)/DM

FD=din∆dreptunghic este DAF (t.p.)

FD=√AF²+AD ²=√12²+8²=√144+64=4√13cm

2DM=4√13-DM

3DM=4√13

DM=4√13/3cm≈4,8cm

Answer 2

Răspuns:

Explicație pas cu pas: