A(n)=ar^(n-1) so
100=4r^9
25=r^9
ln25=9lnr
ln25/9=lnr
r=e^(ln25/9)
a(n)=4e^((n-1)(ln25/9) if you wanted an approximation...
a(n)=4(1.43^(n-1))
Answer:
slope: 
equation: 
Step-by-step explanation:

- point-slope form of Equation of the Line

This is the best i could find
Answer:
Step-by-step explanation:
All the interior angles are of measure 60 degrees.
We want to find the height of this triangle. Call it h. On the left side of this illustration is a right triangle with height h and base (1/2)(10), or 5.
The ratio of height to base is the tangent of 60 degrees:
h
tan 60 degrees = --------------
5
h
and tan 60 degrees = 1.73 = ------
5
Multiplying both sides of this equation by 5 yields h = 8.66. This is |BD|. This is the same as Answer B.