How to resolve 3/5×5/6 by cross canceling

The diameter of a circular chip is doubled to use in a new board game. the area of the new chip will be

He amount of carbon-14 present in animal bones t years after the animal's death is given by p(t)equals=upper p 0 e superscript negative 0.00012097 tp0e−0.00012097t. how old is an ivory tusk that has lost 26% of its carbon-14?

Need on this geometry question. explain how you did it.