246 rule -10
246, 236, 226, 216, 206...
The answer is A, 236
Answer:
x ≈ 8.9
Step-by-step explanation:
Given a tangent and a secant from an external point to the circle, the the square of the tangent is equal to the product of the external part of the secant and the entire secant, that is
x² = 8(8 + 2) = 8 × 10 = 80 ( take the square root of both sides )
x =
≈ 8.9 ( to the nearest tenth )
We rewrite the equation:
y = y0 * e ^ (- 0.0002 * t)
In this equation:
I = represents the initial amount of the isotope
We have then:
89% of the isotope left:
0.89 * y0 = y0 * e ^ (- 0.0002 * t)
We clear the time:
e ^ (- 0.0002 * t) = 0.89
Ln (e ^ (- 0.0002 * t)) = Ln (0.89)
-0.0002 * t = Ln (0.89)
t = Ln (0.89) / (- 0.0002)
t = 582.6690813
round to the nearest year:
t = 583 years
Answer:
There will be 89% of the isotope left in about:
t = 583 years
S’(12,-20) T’(0,-8) U’(-12,-20)