What is the slope of a line that is perpendicular to a line with a slope of -2?

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?

Which of the following is the shape of a cross section of the figure shown below

Peter measures the angles in a triangle. he finds that the angles are 95, 10 and 75. is he correct? explain your answer