Lesson Today 11/19/12

In today's Math class we found out how square roots work.
Examples that was given by Mr. Backe are:

√121=11               √81 =9                         √36=6


√12.1 ≠1.1  because if you use a calculator the answer will be 3.48. But if you estimate it, the easy way to figure it out is to find the closest perfect square in this case √12.1 is close to √9 and √16. Then you find out the distance between √9 and √16 and it will be 7 so the answer will be close to 3 and 3/7. Which is 3.428.

The same thing will happen for √8.1 and √3.6. But √8.1 ≠0.9 and √3.6 ≠0.6, and √3.6 equal to 1.897 and √8.1 equals to 2.846

Here are the other examples:

√1.21=1.1                   √0.81=0.9              √0.36=1.6
√0.121=0.348             √0.081=0.2846      √0.036=0.1847
√0.0121=0.11             √0.0081=0.09        √0.0036=0.06
√0.00121=0.0348

You might realize that there is a pattern. And the pattern is that even amount of even numbers are perfect squares and the ones that have odd amount of decimals are surds. They move one place value.

11²= 11x11=121
1.1²= 1.1x1.1= 1.21
 0.11²= 0.11x0.11= 0.0121

Those are perfect squares.

Another thing we learned is to know how to square root a fraction.

√ 25=    √25  = 5
   49      √49      7

 √64  =  8
  81      9


√36 = 2     √36 = √4=2
   9               9

Homework:
Textbook: pg 72-77
Do Practise: 6,7,9,10,11,13,14
Apply: 15,16,17,18,19,20,22,24,25,27,28,30,31
Extend Any 2 plus 36

Textbook: page 61. Question 15

15. In dry air, the temperature decreases by about 0.65°C for each 100 metre increase in altitude.

  a) The temperature in Red Deer, Alberta, is 10°C on a dry day. What is the temperature outside an aircraft 2.8 km above the city?

The number became 2800 because I converted 2.8 km to metres, so it became 2800. I multiplied it by .65 because the answer determines what to add or subtract it to the current temperature. I divided 1820 to 100 because it would easier to subtract the number to the temperature. I put 10 first because you are subtracting from 10. The temperature outside of the aircraft is -8.20°C.

   b) The temperature outside an aircraft 1600 metres above Red Deer is -8.5°C. Whats is the temperature in the city.

 I multiplied it by .65 because the answer determines what to add or subtract from the temperature. I divided 1040 by 100 because it would be easier to subtract the number to the temperature. The  temperature in Red Deer is -1.9°C.