Use the given values in the compound interest formula to solve for time, n.
A is the final amount of money, $2800
P is the initial or starting amount $1900
i is the interest rate as a decimal 0.025
n is time in years since it annual.
2800 = 1900(1 + 0.025)^n
2800 = 1900(1.025)^n
2800/1900 = (1.025)^n
28/19 = (1.025)^n
take the natural log of both sides to solve for exponent.
ln(28/19) = ln(1.025^n)
power rule of logarithmic moves exponent
ln(28/19) = n*ln(1.025)
ln(28/19) / ln(1.025) = n
put into a calculator
15.7 years = n
Answer:
$122.88
Step-by-step explanation:
the phone decreases by 20% each year , that is
(100 - 20)% = 80% =
= 0.8
the phone reduces by a factor of 0.8 each year , then after 4 years
value = $300 ×
= $122.88
Not sure why such an old question is showing up on my feed...
Anyway, let

and

. Then we want to find the exact value of

.
Use the angle difference identity:

and right away we find

. By the Pythagorean theorem, we also find

. (Actually, this could potentially be negative, but let's assume all angles are in the first quadrant for convenience.)
Meanwhile, if

, then (by Pythagorean theorem)

, so

. And from this,

.
So,
Answer:
The angles that are supplementary to angle 7 includes angle 5 and angle 8.
57,682
I got this by putting the numbers in their place