civonamzuk

I'm going to work in degrees:

pi(2*8) = 50.2654824574366918

(50.2654824574366918/12)*2 = 8.3775804095727819666

364 / (75+65) = 2.6hrs   or 2hrs and 36minutes

A clock has a minute hand 16 cm long and an hour hand 11 cm long. Find the distance between the outer tips of the hand at 2:25 o'clock.

The angle between the clock's hands at 2:25 is 77.5^o.

short hand s = 11cm,  long hand l = 16cm,     d = ? (d is the distance between the outer tips of the hands)

We can use cosine rule:     d² = s² + l² - 2sl cos(A)

                                       d² = 11² + 16² - 2*11*16*cos 77.5^o

                                       d = 17.344cm

         Before                                    After

      5(b) : 9(w)                            13(b) : 15(w)

       5+9=14                                13+15=28        (The total number of tiles must be evenly divisible by 28)  

1/  28/14=2    2*5=10,  2*9=18   if we took 9 tiles out 18 and add them up to 10, the ratio will be 19:9  WRONG!

2/  28*2=56,    56/14=4,      4*5=20,    4*9=36  in this case, the ratio is 29:27  WRONG!

3/  28*3=84,     84/14=6,     6*5=30,    6*9=54   if we subtruct 9 from 54 and add it to 30, we get the desired

ratio:  39 : 45  or   13 : 15   RIGHT!

There are 84 tiles on the floor! 

Here's another method:  Babylonian method of guess and divide

My only problem with this method is=>  division. How long would it take to a 6th grader to divide  20 by 4.4048 without a calculator? 

Finding the square root of 20 using Babylonian method of guess and divide:>

For me, algorithm works best.

Squre root of 645 (the result is above the square root symbol)

Here's a website that explains it very well:>

http://www.homeschoolmath.net/teaching/square-root-algorithm.php

Here's a link for a similar question and answer:>  

http://web2.0calc.com/questions/an-hd-television-has-a-list-price-of-752-if-a-series-discount-of-10-15-is-offered-what-is-the-net-cost-after-the-series-discount-use-the

If the net cost is $504, and the series discount is 10/20/30, what is the list price?

Net cost = $504,       Series discount:  10/20/30,         List price = ?

Net cost equivalent = 0.9*0.8*0.7 = 0.504    

List price = Net cost / Net cost equivalent

List price = 504/0.504 = 1000

              = $1000

An HD television has a list price of $752. If a series discount of 10/15 is offered, what is the net cost after the series discount? Use the method of complements to solve this problem.

The List price = $752,      The series discount is: 10/15   (the complements of 10/15 are: 0.90 and 0.85)

The Net cost equivalent is calculated this way:     0.90 * 0.85 = 0.765                                     

Net cost = List price x Net cost equivalent

Net cost = 752 * 0.765 

              = $ 575.28