In the formula A(t)equals=Upper A0A0 Superscript ktkt, A is the amount of radioactive material remaining from an initial amount Upper A 0A0 at a given time t, and k is a negative constant determined by the nature of the material. A certain radioactive isotope decays at a rate of 0.10.1% annually. Determine the half-life of this isotope, to the nearest year.

693 Years

Step-by-step explanation:

Given an initial amount and k (a negative constant) determined by the nature of the material, the amount of radioactive material remaining at a given time t, is determined using he formula:

If a certain radioactive isotope decays at a rate of 0.1% annually.

The half-life of the isotope is 693 years.

D

Step-by-step explanation:

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k) are the coordinates of the centre and r the radius

(x - 5)² + (y - 4)² = 25 ← is in standard form

with centre = (5, 4) → D