Scientists believe that earth once had 9 trillion tons of a naturally existing plutonium isotope (back when the earth was formed). given a half-life of 24 comma 000 years for that specific plutonium isotope and the earth's current age of 4.6 billion years, how much would remain today? use your answer to explain why this isotope is not found naturally on earth today.

∠acb = 8°

step-by-step explanation:

∠xba lies on the circle and is half the measure of the intercepted arc ax

hence

measure of arc ax = 2 × 42° = 84°

∠acb is outside the circle and is

∠acb = (arcab - arcax ), hence

∠acb = 0.5 (100 - 84) = 0.5 × 16° = 8°

your answer is the frist one

hop i

1. which statement below is true for hyperbolic geometry?

answer: d  

the sum of the measures of the angles in a triangle is always less than 180 degrees.

2. identify the statement that is true in spherical geometry.

answer: d  

the sum of the measures of the angles of a triangle is greater than 180.

3. what can be said about the vertices of an equilateral triangle drawn in poincaré’s system?

answer: b  

the vertices are equidistant from the center of the circle.

4. satellites sputnik, yeltsin, and plekov often temporarily line up in order in a great circle. the circumference of the earth is 24,900 miles, and the satellites orbit at about 150 miles above the surface. if, while in a great circle, sputnik is 9,000 miles from yeltsin, and yeltsin is 10,500 miles from plekov, how far apart are sputnik and plekov?

answer: b  

6,342 miles

5. identify the statement that is true in spherical geometry.

answer: d  

two distinct lines intersect in two points.