- three cubes of a metal whose edges are in ratio 3:4:5 are melted and converted into a single cube whose diagonal is 12root 3 cm find the edges of the three cubes .
- a right triangle ,whose sides are 15cm nd 20cm,is made to revlve about its hypotenuse. find the surface area of the double cone so formed.
Let the edges of the three cubes = 3x, 4x and 5x
Given : The length of the diagonal of the single cube =
As we know that,
the length of the diagonal of a cube of side
⇒ edge of the single cube = 12 cm
Volume of the single cube = (12 cm)3 = 1728, cm3
Since the three cubes are melted and converted into single cube
⇒ Sum of volumes of three cubes = volume of single cube
∴ The edges of the three cubes are 6cm, 8cm and 10 cm.
Consider the following right angled triangle ABC is rotated through its hypotenuse AC