Task 18 - 26

Task 18
If I had a random number in cell A2, how could I get it into standard form using Excel functions.

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http://iforce.co.nz/i/dsu0udey.col.png

Task 19
Write a paragraph in your blog explaining how the Sieve of Eratosthanes works. Construct a table that shows the Sieve and write down the first 20 prime numbers. If possible use colour and fonts to show the number patterns.

The sieve of Eratosthenes is one of the most efficient ways to find all of the smaller primes, you start by making a grid of numbers. First start at multiples of two and cross them out, then move on to multiples of three and so on...

Eventually you will have left over numbers that you havn't crossed out, those left overs are prime numbers, an image GIF is provided below to further explain.

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http://upload.wikimedia.org/wikipedia/commons/b/b9/Sieve_of_Eratosthenes_animation.gif

Task 20

Areas. Circles. Have a go at these problems on areas of circles.Take a screen shot of the page and put into your blog.

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http://iforce.co.nz/i/l0snwp2s.0kq.png

Task 21

Find a web page that deals with Pi. Take a screen shot of one that interests you.

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If image error click link provided:

http://www.joyofpi.com

Task 22

What does Excel say that Pi is?

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http://iforce.co.nz/i/llfbukoc.ij5.png

Task 23

Construct a cell in Excel that gives a random radius between 0 and 10. Beside it calculate the area of a circle with that radius.

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http://iforce.co.nz/i/1skp2kxz.mro.png

Task 24

Write a blog post that illustrates the area of a rectangle. You'll need a diagram, formula and explanation.

Here we have a rectangle that is two units high and 4 units across.

The math to work out the area of a rectangle is:

Base x Height

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http://iforce.co.nz/i/nnqe5w2y.mhc.png

Task 25

Repeat 24 for the area of a triangle.

A triangle is basically half of a rectangle.

The formula we use to calculate the area a triangle is:

½ x base x height

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http://iforce.co.nz/i/asfjm30j.5uj.jpg

Task 26

Repeat 24 for the area of a circle.

Radius = 1/2 diameter 

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If image error click link provided:

http://iforce.co.nz/i/2t4a0cz1.3nh.png