Question

find the perimeter of the rectangle whose length is 40 cms and a diagonal is 41 cms

Answer 1

By Pythagoras theorem,
D^2 = L^2 + B^2
=> B^2 = D^2 + L^2
= (41)^2 - (40)^2
= 81
=> B = 9 cms
Now,
Perimeter = 2(L+B)
= 2(40+9)
= 2(49)
= 98 cms

Answer 2

9,40 ,41 ( Pythagoras triplet)
here 9 is breadth
perimeter = 2 (l+b)=
= 2× 49 = 98 cm