Question

a) In the given figure D and E are
the mid points of side AB and AC
respectively. AB = AC = 10 cm,
perimeter of AABC = 28cm and an-
gle A = 40°, find
(i)the length of DE (ii)angle ADE​

Answer 1

rimeter of triangle ABC is 28.

Then side BC=28-(10+10)=8

D,E mid point of AB,AC

Therefore side DE=1/2 BC=8/2=4

angle A=40°

DE parallel with BC

side AD and AE R equal

angle ADE=(180-40)/2=70°

Answer 2

Answer:

lenth of de is 4cm

angle ade is 70°

explanation

here,

given perimeter = 28

therefore 10+10+BC = 28

therefore BC = 8cm

now, since de is paralell to bc therefore using mid pt theroem

de= bc/2=4cm

now for angle ade,

first finding angle abc using angle sum property

40+Angle abc +angle acb = 180

since angle abc is equal to angle acb

therefore angle acb=angle abc =70°

now angle ade = angle abc ( corresponding angles )

therefore angle ade = 70°