# angle

1. ### Triangle in a cyrcle

Does anyone know how to solve this? It has no information, just the answer is given, which is 72deg.
2. ### Finding the angle and axis lengths of an ellipse

Hi, I have an ellipse defined by \|\mathbf{A}^{-1}v\| = 1, where v is a vector in the ellipse and \mathbf A is a real, invertible 2-by-2 matrix. How can I find the lengths of the axis of the ellipse as well as the angle of the major axis? I need to know this because I want to plot the ellipse...
3. ### Find the angle ADB

Can any one help me finding the angle ADB if ACB = 30, CD = DB ?
4. ### formula for the angle between two intersectiing planes

Hello, Referring to the picture below, I have 4 points in orthogonal 3D space (sorry if I couldn't make the picture look more 3d). The vectors AB and BC lie in an Euclidian plane while the vectors AB and BD lie in a different Euclidian plane. These planes intersect along the vector AB. I am...
5. ### How can measure of a minor arc is equal to measure of its central angle in a circle?

How can measure of a minor arc is equal to measure of its central angle in a circle?
6. ### Find the angle

Can anyone help me finding the angle ADB ?
7. ### find the angle between two lines formed by three points in n-space

Hello, I wasn't sure where to post this, so please feel free to move it. In some ways, I suspect this is a very elementary question for an expert, so I posted in on the pre-university side. Here is an example in 2D of the problem I am looking at, given three sets of coordinates...
8. ### Find the angle X

Hi Please Help me to find the angle X with reasons.(Diagram attached) BD & CD points are on BE side of the ▲ABE. AC=DE. Find the value of angle X
9. ### angle outside triangle

this is actually mohr's circle formula, forget about the theory,let's focus on the mathematics part. I couldnt understand why the tan( 2 θs1) = -(σx -σy) / 2τxy ? 2θs1 is outside the triangle theorically, tan(180-α )= -tan( α ) , so tan( 2 θs1) = -(σx -σy) / 2τxy , the vertical staright line of...
10. ### limit of angle

can someone explain about the limit of ∅ is taken from 0 to pi only?
11. ### Triangle with Angle,Side,Ratio known

Hello everybody, I've got a triangle with 1 angle, 1 side and the ratio of the other 2 sides known. But no matter what I do, I keep running in circles. Is there a way to leave the unknown "d" alone in one side of the equation?
12. ### Trig angle Formulas

Hey, I am confused as to how to break down this question. "Evaluate using formulas developed in this section." a) sin 11pi/12 the formulas are the addition and subtraction as well as double angle formulas. i know that 11pi/12 = pi/3 + pi/4 + pi/4 + pi/6 but am not sure how to turn it into a...
13. ### If (a,b) is a point on the terminal side of angle t in standard position, then cos(t)

How do I know what it is supposed to be? Please explain. Thank you!
14. ### long question , confusing , please check them for me,urgent!!!

Same as the title, please figure out what is wrong for my working ,, questions: 1)A helicopter takes off from a point 120m away from an abserver located on the ground, and rises vertically at a constant rate of 2.5m/s.At what rate is the elvation angle of the observer's ine of sight to te...
15. ### Find radian measure of a centralized angle

Circle radius is 1cm. Area of certain sector is pi/5cm^2 What is the radian measure of the central angle. Do I do C= 2pi(1) then 2pi*5cm^2?
16. ### Parallelogram Help?

A parallelogram exists within a rectangle which measures 15 inches tall by 20.5 inches wide. A=15 inches B=20.5 inches C=1.5 inches (C makes a 90° angle with X) Solve for lengths X and Y and angle Z of the parallelogram and please tell me how you did it!
17. ### Help calculating a point in 2d space on a rotating right angle triangle

I am trying to solve for a point on a triangle that rotates around a fixed point. For ease of calculation this point is at X: 0 Y: 0 The length and width of the triangle are always fixed, the only thing that changes is the rotation angle. How can I solve for X: ??? and Y: ??? taking into...
18. ### Proving angle equivalency

Hi everyone, Is there a way to prove that angle B and angle C are equivalent in this situation? The argument my textbook made certainly seemed to imply that, and it really bothers me that I can't quite see it. I'm worried it's really simple and I'm overthinking it... I haven't taken geometry in...
19. ### find an angle

Hi! I have a trig problem. I need to find the angle EAB. All known sides and angles you can find on the sketch right here: Any help greatly appreciated.
20. ### Two Different Angle Vector Formulas ?

Formula to find the angle between vectors: |a|\,\,|b| = \cos\theta or \cos\theta = \dfrac{a\,\,*\,\,b}{|a|\,\,|b|} where a and b are vectors When should we use one formula rather than the other?