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#1 2005-11-24 01:12:31

robin
Member
Registered: 2005-09-23
Posts: 3

Help a dad - Triangles

Hi,

My kid brought some homework back and I sat down to help...... And got stuck *blush*
Well, his homework was easy, find the missing length or angle of a triangle etc.  We finished that with no problems and I felt quite happy I seemed to of helped, but then he asked me about angles of a triangle -
Why are the angles always an exact figure, like 45 degrees or 61 degrees.

I should of just said, thats what the book says, but no, I went into explaining that the angles can have decimals and tried to explain about the Angle being built with Degrees and minutes / secs ... This sank in and then he said, -
What tangent should be used for a 32.47 degree angle  ?

I grinned and opened the Trigonometric table page and found 32 degrees = 0.625
and 33 degrees = 0.649.. And said it lies within these too tangents.

But.... I couldn't explain what the exact tangent to use would be. I told him we'd revisit the problem and so here i am.... I've searched the net and havent found any such precise tangent tables or anything which will help me to understand and explain better the solution.

Sorry its a long one... Any help on this would be appreciated.


Robin

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#2 2005-11-24 04:46:40

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: Help a dad - Triangles

A scientific calculator could tell you.

The calculator in the 'accessories' bit of your computer has a scientific mode, or you could use Microsoft Excel and put

=tan(radians([angle])), where [angle] is the angle that you want the tangent of in degrees. That would tell you the value to at least 10 decimal places, I should think.


Why did the vector cross the road?
It wanted to be normal.

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