Asample of a radioactive isotope had an initial mass of 690 mg in the year 1997 and decays exponentially over time. a measurement in the year 2001 found that the sample's mass had decayed to 390 mg. what would be the expected mass of the sample in the year 2011, to the nearest whole number?

30 pts, will mark brainliestwhat is the period of the sinusoidal function? (picture 1)what is the minimum of the sinusoidal function? (picture2)what is the maximum of the sinusoidal function? (picture 3)

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?

What is the circumference of the pie