ElectricPavlov

Cos 2theta = -4/5

ARCcos2 theta = arcos (-4/5)

2theta = 143.13 degrees

theta = 71.565 degrees      BUT this is in the WRONG range of  90 - 135     SO we need to find the value in the second quandrant which corresponds to 71.565

180 - 71.565 = 108.435 degrees

 Sorry Guest, you got the wrong numbers too!      

CORRECTED (DUE TO USING  4350800 MISTAKENLY INSTEAD OF 43508000)

29.2 /4350800  =  100/x

x = 100/29.2  * 43508000 = 149,000,000  sq km = Earth's surface total area  (land surface is given as 43508000)

As a ratio: (TO FIND WATER SURFACE)

70.8/29.2  =  x/ 43508000

x =  70.8/29.2   * 43508000  =  105,492,000 sq km   is the water surface area

CHECK:  TOTAL AREA - LAND AREA = WATER AREA

                149000000 - 43508000 = 105,492,00  sq km                 OK!  Finally !

1  6  9 12  12  14  25        Mode is the number that appears the most frequently = 12  

                                          Median is the number that has the same number above it and below it...it is in the middle of the list of numbers    = 12

                                            Mean is the average of the numbers  ...add them all up and divide by 7    = 11.286

Since we are compounding MONTHLY, we need to look at the MONTHLY INTEREST RATE    (assuming APR does NOT account for compounding already)

2.75 / 12 = .229167 % / month

12 years is 12 x12 interest periods (months) = 144

fv = pv (1+ i ) ^t     where i is interest rate in decimal  = .00229167    and t is the time periods  144    fv = future value  pv = present value (5700)

fv = 5700 (1+ .00229167)^144  =  7925.53

2.25/2.5  x  15.60  =  14.04

As a ratio   15.60/2.50  =  x / 2.25     15.60/2.5  * 2.25 = x  = 14.04

2 to the second power   is   2^2 = 4

Sqrt (64) = 8                                            the fraction of 4 to 8   is 4/8 = 1/2

29.2 /4350800  =  100/x

x = 100/29.2  * 4350800 = 14,900,000  sq km

As a ratio:

70.8/29.2  =  x/ 43508000

x =  70.8/29.2   * 4350800  =  10,549,200 sq km

If you need to square negative twelve , you have to do it like this:  (-12)^2 = 144   (must use parentheses....)

Well...THAT's a horse of a different color from the original question (I assume you) posted

fv=pv (1.05)^8 = 8864.73

Yah,  I knew that.......