Answer:
h = 9 ft
Step-by-step explanation:
Assume the diagram is like the one below.
∆ABD is a right triangle.
We can use Pythagoras' Theorem to find the height h.

Answer:
-72=-72
Step-by-step explanation:
5n-42=12n
n=-6
5*(-6)-42 = 12*(-6)
-30-42=-72
-72=-72
So, n= -6 is the right number for this equation
17,190 / 5,730 = 3. This means we must divide 70mg in half 3 times
70 / 2 = 35
35 / 2 = 17.5
17.5 / 2 = 8.75
There will be 8.75 mg left after 17,190 years.