Find the length of the side of rhoumbus whose diagonals are of length 6cm and 8cm.

In a rhombus, the diagonals bisect at right angles. That means half the diagonals form a right angle triangle then we can try the Pythagorean theorem. so -

one side of triangle =  6/2 =3 (half of the diagonal)

other side = 8/2 = 4

a^2 + b^2 = c2

3 ^2 + 4^2 = c^2

9+16 = c^2

c^2=25

c = = 5

the hypothenus forms one side of the rhombus and here the hypothenus is 5, so the lenght of a side is 5 !

b is the correct answer