Question

Exercitiul 12 si 13 !!

Answer 1

12a) 3x=90, unde x=90:3 = 30°, atunci 2x=60° (∡AOC), iar ∡COB=30

b)6x=90, unde x=90:6 = 15°, 3x=45°(∡AOC), 2x=30°(∡COD) si DOB=15

c) 16+2x+5+x=90, 3x=90-21, x=69:3=23°, 2x+5=51°(∡COE), EOB=23, iar AOB=16°

d)2x+4+x+10+x=90, 4x=90-14, x=76 : 4=19, ∡AOC=42°(2x+4), ∡COD=29° si DOB=19°

e)= (90-20) : 2=35°(bisectoarea DO), atunci AOC=35*2=70

f) = DOC=90-(34*2)-10=12, AOE=EOD=34

g) BOE=EOD=39°, iar BOD=39*2=78°, atunci AOD=BOA-BOD=90-78=12, unde AOC=12:2 =6 si AOC=COD=6°

h) DEO=EOF=15, unde DOF=15*2=30°

AOC=COD=22, iar AOD=22*2=44°

FOB=AOB-AOD-DOF=90-30-44=16, atunci FOG=GOB= 16: 2 =8°,

13) a)∡AOB=180, unde 3x+x=180, 4x=180, x=180:4 = 45, AOC=3*45=135

b) ∡AOB= 180, unde x+x+100=180, 2x=180-100, x=80:2=40, ∡COB=40+100=140

c) ∡AOB=180, unde 102+2x+x=180, 3x=180-102, x=78:3=26, ∡COD=26*2=52, si DOB=26

d)x+3x+20=180, 4x=180-20, x=160:4=40, AOC=40, iar COB=3*40+20=140

e) 2x+3x+72+x=180, 6x=180-72, x=108:6=18, AOC=2*18=36; COD=3*18=54 si EOB=18

f)

60+2x+40+2x+x=180, 5x=180-100, x= 80:5=16, EOD=2*16+40=72, DOC=2*16=32 si COB=16