what is the area for the trapezoid

Bismuth-210 is an isotope that radioactively decays by about 13% each day, meaning 13% of the remaining bismuth-210 transforms into another atom (polonium-210 in this case) each day. if you begin with 233 mg of bismuth-210, how much remains after 8 days?

In the figure shown below, m < 40 and ab =8. which equation could be used to find x?

The angles below are supplementary. what is the value of x? a pair of supplementary angles is shown. one angle measures 7x + 33, and the other angle measures 70. 5.3 8.14 11 14.7