Question

19.The sides of two squares are in the ratio 5:7. Find the ratio of their areas.
20.Can two numbers have 16 as HCF and 390 as LCM? Give reason.​

Answer 1

The sides of two squares are in ratio of 5:7.

Let the sides be 5x and 7x.

Now area of a square is given by side square,.

So area of square with side = 5x will be (5x)^2 = 25x^2.

Now area of square with side = 7x will be (7x)^2 = 49x^2.

Ratio = 25x^2/49x^2.

From above x^2 gets cancelled so the ratio (final answer) will be 25/49.

Coming to the next question.

We know that H.C.F. between the numbers is the 'highest common factors' between two numbers while L.C.M. is the 'lowest common multiple' of that numbers. Two numbers with both H.C.F. as 16 and L.C.M. as 380 is not possible.