Step-by-step explanation:
Given c = longest of triange = 15m
Given b = short side of triangle = 9m
By pythagoras' Theorem,

There will be a 25 grams left after 3240 years.
The half-life of Radium-226 is 1620 years. If we divide 3240 by 1620 the answer is 2. So that means the amount of Radium-226 will divide in half twice.
100 / 2 = 50 / 2 = 25
This equation does not factor...