+0  
 
0
286
3
avatar

How to you find the value of missing angels in a triangle? I looked it up on google and there was this law thing but I'm in applied math and my teacher said something about z and c patterns

Guest Jun 18, 2015

Best Answer 

 #3
avatar+4663 
+10

Rule One: All triangles add up to 180º.

 

REMEMBER:

 

Equilateral Triangle: All sides are the same : 60 + 60 + 60 =180

 

Isosceles Triangle: Two sides the same : E.G. 50+ 50 + 80 = 180

 

Scalene Triangles: All sides different : E.G. 50+ 30 + 100

MathsGod1  Jun 19, 2015
Sort: 

3+0 Answers

 #1
avatar
+5

The method used depends on the situation:

▪ The "Z" method is simply if you have two parralel lines, and are joined by a straight line (Either in a Z shape or a _/‾ shape) the 'inside' angle at either side will be identical, and the 'outside' angle at either side will also be identical. This will rarely apply to triangles however.

▪ If you know 2 angles already, then you can use the fact all 3 angles of a triangle add together to equal 180. So, 180 subtracted by the other two angles will give you the third angle.

This is the simplest and most often needed.

The rest I am going to mention needs some work with forumlae. Depending what level of mathmatics you are working with, these may or may not be relevant at all.

▪ If you know the length of a side opposite a known angle, you can work out the value of any other angle as long as it is opposite to another known side using the "Sine" rule.

Sine(A)/a = Sine(B)/b

Re-arranged this can be used as:

A = asin((a * Sine(B))/b)

▪ If you know 2 side lengths but the known angle is not opposite either, you can use the "Cosine" rule to work out the third side. From there you can use the Sine rule to work out the other angles.

a^2 = b^2 + c^2 - 2bc Cosine(A)

This rule can also be used to find any angle if you know all 3 sides, by re-arranging the forumla to:

A = acos((b^2 + C^2 - a^2)/2bc)

Guest Jun 19, 2015
 #2
avatar+90968 
+10

You might find this helpful

https://www.mathsisfun.com/geometry/parallel-lines.html

 

alternate angles make a z shape

Co-interior angles make a C shape

and 

Corresponding angles make an F shape.

 

--------------

If you scroll down on this one it willshow you the Z, C and the F very clearly :)

http://passyworldofmathematics.com/angles-and-parallel-lines/

Melody  Jun 19, 2015
 #3
avatar+4663 
+10
Best Answer

Rule One: All triangles add up to 180º.

 

REMEMBER:

 

Equilateral Triangle: All sides are the same : 60 + 60 + 60 =180

 

Isosceles Triangle: Two sides the same : E.G. 50+ 50 + 80 = 180

 

Scalene Triangles: All sides different : E.G. 50+ 30 + 100

MathsGod1  Jun 19, 2015

21 Online Users

avatar
avatar
avatar
avatar
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details