The half life of a certain radioactive material is 68 hours an initial amount of the material has mass of 641 kg. write an exponential function that models the decay of this material. find how much radioactive material remains after 4 hours. round your answer to the nearest thousandth

a)

b) Radioactive material remain after 4 years = 615.39 kg

Step-by-step explanation:

we know that the general equation of exponential decay is:

where,

A is amount after time t

P is the initial amount =641 kg

k is a constant

t is time  period

The half-life of a certain radioactive material = 68 hours

The required equation will be :

For t=4 years

Radioactive material remain after 4 years = 615.39 kg

last option

step-by-step explanation:

given that δdef is right and isoceles,

assuming that side df is the hypotenuse means that de an ef are the other 2 sides that intersect at 90° and are of equal length.

because they are of equal length, we can say that they are congruent

because they intersect at 90°, their slopes must be opposite reciprocals.

only the last option satisfies these conditions.

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