Y11+Trigonometry+topic+page.

=Right-Angled Triangles= media type="youtube" key="_S35Ht4imhs" height="344" width="425" The main skills you need for this topic are:
 * know whether a question will require Pythagoras or Trigonometry
 * Be able to select the right rule (Sin? Cos? Tan? Pythag?)
 * WRITE A CLEAR EQUATION
 * See what working is required (multiply, divide, inverse, squaring/rooting)

Trig or Pythag?
The triangle on the LEFT would have to be a Pythagoras question. If no angle is selected, you cannot find sides that are opposite and adjacent...so you can't choose any of the three trig rules!

The triangle on the RIGHT could be for a Trig question.

Pythagoras's Theorem
"short side squared plus short side squared equals long side squared"

You can work out questions numerically or with a diagram.

Square the lengths. Add (because you need the longest side). Square root to get your answer.

Add to get the missing AREA. Area = 34. Square root 34 to get the length of side x (5.83 to 2 d.p.)

Square the lengths. Subtract them (because you need one of the smaller sides). Square root the answer to get length x. Subtract the areas to get the missing area (65). Square root the area to get the length of side x (8.06 to 2 d.p.)

=TRIGONOMETRY=

Labelling sides - this is necessary to choose the correct rule (sin, cos or tan)
media type="youtube" key="hJH_FDbcmSg" height="344" width="425"
 * H ** = hypotenuse (longest side, opposite the right angle)
 * O ** = opposite (opposite the angle)
 * A ** = adjacent (the side AGAINST the angle)