A new radioactive isotope was discovered in fossilized amber. You put the amber in a time-capsule today with a note that the amber contained 20g of Isotope-X. If a person discovers your time capsule in the year 3660, and measures that there is now 13g of Isotope-X in the amber, how long is its half-life?

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

Anyone know? will mark brainliest if correct!

Find the measure of the interior angles of the following regular polygons: a triangle, a quadrilateral, a pentagon, an octagon, a decagon, a 30-gon, a 50-gon, and a 100-gon.