D and E are respectively the point on the side a b and ac of a triangle ABC such that ad is equal to 2 cm BD is equal to 4 cm BC is equal to 9 cm and DE is parallel BC then find the length of DE
Answers
Answer:
because DE=EF, so you can say that angleD=angleF
now as everyone knows the sum of three angles is 180 degrees, so....
angleD+angleE+angleF=180
[you can put angleD in place of angleF because both are similar]
so,
angleD+angleD+angleF=180
2*angleD+30=180
2*angleD=180-30
2*angleD=150
angleD=150/2=75
so, here we have got the value of angleD which is 75 degrees. Hope it helped, [and what is anh?]
ok, here's what you want.
firstly, construct De=5cm.
2.the construct ∠E which is 30 degrees.
3.and finally make an arc on EF↔ with the measurement of 5 cms.
3.then construct DF which will be of 5 cms exactly.
4.m∠D=75 [how? It's already
GIVEN:-BD=2cm
DB=4cm
BC=9cm
DE||BC
TO FIND:-DE=??
LET DE=X
NOW,,,,
When DE //BC then
then the line divides the
two lines in distinct points. (by BPT)
hence the sides are in ratio
hence...... AD/BD=AE/EC=DE/BC
AD/BD=DE/BC
2. /4=x/9
x=4.5
Therefore,,,DE=4.5cm
