Still having trouble, all this is familiar but it's like something is blocking my brain Having problems with all questions, for the first 3 questions I forgot how to solve for the values if I have a number inside the triangle. I remember a bit of doing something with the 2nd function on the calculator; but I dont even have a scientific calculatoron on me
I am a dead loss !
Now I realize how important it is to listen to the teacher, this teacherless online course kills my brain cells.
In any triangle ABC, side a is opposite angle A, etc, and we have:
In question 1: you're not interested in a or A, so plug the values of B, C and c into the last two parts of the formula and solve for b.
Cosine Rule: There are three. Here's the first:
The other two just move all the letters around one place: , etc. So you get:
In question 2, you have to make up a similar rule using letters p, q and r. Then plug the values of q, r and P in, and solve for p.
In question 3, write down the Sine Rule using the letters x, y and z, and then use x = 34, X = 110 degrees, z = 15, and solve for Z.
That should get you started.
If a side is labelled a (say), then the angle opposite the side a is given the symbol A. Similarly side b has an opposite angle labelled B and side c has an opposite angle labelled C.
Can you label the sides and angles?
Can you identify what it is you are trying to find (which side or angle)?
Can you see that it's opposite side or angle is defined.
Can you see that there is another side with its opposite angle defined?
Plug these things into the sine rule and you should be able to solve for the unknown.
Have a go. You have to try these things yourself and make your own mistakes. We can show you where you've made your mistakes and help to rectify them. We're here to help guide you in the right direction, not to do your homework.
Here are some worked examples that might help to give you some ideas:
Solve triangle - SSS
And, if you have Powerpoint, this one is great: http://www.btinternet.com/~mathsanswers/Sine_Rule.ppt
To give you more of an idea for when they're used;
1. two angles and any side (sine law)
2. two sides and an angle opposite one of them
3. two sides and a contained angle(cosine law)
4. three sides(cosine)
Alright so for 1/ you have two angles and a side, therefore you must use the sine law.
Simply look at what you are given, and make the necessary substitutions into the sine and cosine laws.
Follow the same steps and laws for the others
When you've got , find angle Y using angle sum of triangle = , then use the Cosine Rule:
The formula you need here is: area of triangle =And I also need help with number 6
Draw the diagram as a triangle ABC, marking angle A as the position of the second post, with B and C as the first and third posts. Can you see that angle A = , b = 170 and c = 250? Plug these numbers into the formula, and you've got it.