Thread: trigonometry Addition Formulae (v)

The diagram shows a kite whose leading diagonal forms the diameter of a circle. Find the exact value of sin XOY

What I want to know is, do I need to find the diameter, if so, how?

Originally Posted by r_maths

The diagram shows a kite whose leading diagonal forms the diameter of a circle. Find the exact value of sin XOY

What I want to know is, do I need to find the diameter, if so, how?

That means the inscribed angle X0Y is 90 degree.
Thus, sin 90 = 1

Originally Posted by ThePerfectHacker

That means the inscribed angle X0Y is 90 degree.
Thus, sin 90 = 1

my bad, the sides are not equal so you cant 360/4.
root 5 & 3 are the length of the sides of the kite

the answer is 3 root5 / 7
i dont know how to arrive at that.
(just to let you know, no calculator allowed)

Hello, r_maths!

The diagram shows a kite whose leading diagonal forms the diameter of a circle.
Find the exact value of .

Look at half of the kite . . .

Code:

      Z
      *
      | *   _
      |   *√5
      |     *
   __ |   90° * Y
  √14 |      *
      |     *
      |    *
      |   * 3
      |θ *
      | *
      |*
      *
      O

Since is a diameter,

Using Pythagorus, we find that: .


Let
Then: .

Then: .

Originally Posted by Soroban

Hello, r_maths!


Look at half of the kite . . .

Code:

      Z
      *
      | *   _
      |   *√5
      |     *
   __ |   90° * Y
  √14 |      *
      |     *
      |    *
      |   * 3
      |θ *
      | *
      |*
      *
      O

Since is a diameter,

how did you work out that angle was 90 ?