Question

Solve ques. 7 and 8 ...I need correct and..

Answer 1

See the diagram for both Qn 7 and Qn 8.

DG and EF are perpendiculars from points D and E respectively onto the base BC.

Qn 7:  part (i)

Given DE || BC.
=>  DG = EF
=> 1/2 * BC * DG = 1/2 * BC * EF
=> ar(ΔBCD) = ar(ΔBCE)         ------(1)

ar(ΔACD) = ar(ΔABC) - ar(ΔBCD)
                 = ar(ΔABC) - ar(ΔBCE)     using (1)
                 = ar(ΔABE)
Hence proved.

Qn7 part (ii):

From part (i),                    ar(ΔBCD) = ar(ΔBCE)
             =>     ar(ΔBCO) + ar(ΔOBD) = ar(ΔBCO) + ar(ΔOCE)
            =>                         ar(ΔOBD) = ar(ΔOCE)
Proved.

==================
Qn 8.
See the diagram.

Given
              ar(ΔBCE) = ar(ΔBCD)
=>   1/2 * BC * DG = 1/2 * BC * EF
=>                    DG = EF

As the perpendiculars DG and EF onto BC from D and E, are equal :
                DE || BC.

Proved.

Answer 2

Answer done here.........
@@ @@ @@ @@ @@
Please mark the answer as brain list answer