What is the "vertical” cross section of a cone that if a plane crosses through the tip of the cone?

Name each raycalculation tip: in ray "ab", a is the endpoint of the ray.

Look at this pattern ; 1,4,9, number 10000 belongs in this pattern . what’s the place of this number?

Suppose that sahil knows that 45 people with ages of 18 to 29 voted. without using a calculator, he quickly says then 135 people with ages of 30to 49 voted. is he correct? how might sohil have come up with his answer so quickly?