Question

the perimeter of a rhombus is 20cm one of its diagonals 8cm find the area of the rhombus and the length of other diagonal

Answer 1

area of rhombus = 1/2*d1*d2
= 1/2*20*8
= 20*4
= 40cm

Answer 2

perimeter of rhombus is 20 cm
actually all sides of rhombus are equal ...
so each side will be 20/4=5
now
imagine a rhombus,
D1=8cm
half of that diagonal is 8/2=4
in that triangle by using Pythagoras thm
5*5=4*4+X*X
25=16+X*X
X*X=25-16
X*X=9
so X =3
now it is half of D2
so
3=1/2*D2
1.ans.....so D2=6
area of rhombus = 1/2*D1*D2
=1/2*8*6
=1/2*48
=24
2nd ans is area is 24 sqcm....