Suppose $\triangle DEF$ is isosceles and $\overline{DE}$ is twice the length of $\overline{EF}.$ If the triangle has perimeter $80,$ how long is the shortest side?

Aquantity with an initial value of 3900 decays exponentially at a rate of 35% every hour. what is the value of the quantity after 0.5 days, to the nearest hundredth?

Which of the following are accepted without proof in a logical system? check all that apply.

Using only odd number for numerators write two different subtraction problems that have a difference of 3/4