Question

find the perimeter of rectangoe whose length is 40cm and diagonal is 41cm

Answer 1

let the rectangle be abcd .
in triangle abd .ad is the hypotenuse.
therefore  ad=9 using Pythagoras theorem.
so perimeter of the rectangle =2(l +b)
=2*(40+9)=2*49=98cm
i hope this helps u...

Answer 2

if you see it carefully you will find a right angled triangle and we will use the phytogorous's theorem.
that is hy²=b²+p²
and,p²=hy²-b²
p²=(hy+p)(hy-p)
p²=(41+40)(40+41)
p²=81*1
p²=81
p=9
that is why we got the breadth of the triangle which is 9cm.
perimeter=2(l+b)
=2(40+9)
=2*49
=98cm
that is why the perimeter is 98cm.