The area of a square is $$𝑑.$$ What is the area of the circle which has the diagonal of the square as its diameter?

What would be the smallest natural number which when divided either by $$20$$ or by $$42$$ or by $$76$$ leaves a remainder of $$7$$ in each case?

What would be the smallest natural number which when divided either by $$20$$ or by $$42$$ or by $$76$$ leaves a remainder of $$7$$ in each case?

Find the smallest number $y$ such that $y \times 162$ is a perfect cube.