Find the perimeter of a rhombus whose one diagonal is 16 cm long and area is 240 cm².

68 cm

Area =1/2× (d1×d2), 

where d1 and d2 are diagonals

240 =1/2 × 16 × d2 

d2 = 30cm

If both the diameters of the rhombus are = 30 and 15

then,

with the help of pythagorous theorem,

AB = \(\sqrt {8^2 + 15^2}\) = 17

Now the perimeter = 17 × 4 = 68 cm