In a nuclear disaster at Chernobyl in April 1986, approximately 12,600 kg of radioactive iodine-131 was released into the atmosphere. Iodine-131 is know to decay by half every 8 days.
How many kilograms of iodine-131 remained after 24 days?

In the following diagram it is given that dec,ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2