Note that 8.00 = (2.00)^3, that implies that a decay to 1/8.00 means that the Carbon-14 has passed 3 half-life. (1 to decay to 1/2, other to decay to 1/4, and other to decay to 1/8). And, three half-life is 3 * 5730 years = 17,920 years. So,<span> the answer is that the plant was alive 17,920 years.</span>
Remark
The point value is (-2,5) So we know the two sides. We need the hypotenuse. We should notice that the x value is minus (-2) and value is y value is plus (5). That means we are in quad 2. Be careful how you read that. (-2,5) is a point. It is not a tangent.
Step One
Find the hypotenuse.
a = - 2
b = 5
c = ??
c^2 = a^2 + b^2
c^2 = (-2)^2 + 5^2
c^2 = 4 + 25
c^2 = 29 Take the square root of both sides.
sqrt(c^2) = sqrt(29)
c = sqrt(29)
Step Two
Find the Cosine of the angle.
Cosine(theta) = adjacent / hypotenuse
Cosine(theta) = -2 / sqrt(29) <<<<<<< Answer
Again, watch out for what you are given.
Answer: r = - 20
Step-by-step explanation:





Since the number ranges between 3 and 10, an equation can't be made because the number is always unknown or can be different every time