Question

No.6 ...do if u dare

Answer 1

Answer: 16cm²

Step-by-step explanation:

Given,

Let, height be 'H'

    base be 'B'

so, area of triangle ABC= 1/2BH  

   64= 1/2 * B*H

  64*2= B*H

   B*H= 128 cm² ....(1)

From the figure, (in triangle BDE)

b=1/2B (as E is mid-point of BC)........(2)

And according to mid- point theorem,

D and E are mid points of AB and BC

so, DE=1/2AC & DE parallel to AC

Other side BD is also a half of AB,

and in a triangle if two sides (excluding base) gets halved, then height gets halved

h=1/2H.........(3)

From equation (1),

BH=128

From(1),(2) and (3);

2b*2h=128

bh=128/2*2

bh=32cm²........(4)

Area of triangle BDE = 1/2bh=1/2*32 (from (4), bh=32)

                    =16 cm ²

if you are looking for solution for eight std., I'm sorry, I can't help....

Still, I hope it helps. :)