Solve problems involving two right-angled triangles
The next step in our trigonometric problem solving adventure is to solve 2, 3 or more step problems. What I mean is, solve problems where you have to solve other intermediate steps along the way.
The best way to learn these is to watch some examples, and then try the set of questions.
You'll need to remember these right-angled triangle rules:
Pythagoras' theorem: $a^2+b^2=c^2$a2+b2=c2, where $c$c is the hypotenuse
$\sin\theta=\frac{\text{Opposite }}{\text{Hypotenuse }}$sinθ=Opposite Hypotenuse = $\frac{O}{H}$OH
$\cos\theta=\frac{\text{Adjacent }}{\text{Hypotenuse }}$cosθ=Adjacent Hypotenuse = $\frac{A}{H}$AH
$\tan\theta=\frac{\text{Opposite }}{\text{Adjacent }}$tanθ=Opposite Adjacent =$\frac{O}{A}$OA
Angle of Elevation: the angle from the observer's horizontal line of sight looking UP at an object
Angle of Depression: the angle from the observer's horizontal line of sight looking DOWN at an object
Exact value triangles: 
Examples
Question 1
Consider the following diagram.
Find the length of $AD$AD, correct to two decimal places.
Find the length of $BD$BD, correct to two decimal places.
Hence, find the length of $AB$AB correct to two decimal places.
Question 2
Consider the following diagram.
Find $y$y, correct to two decimal places.
Find $w$w, correct to two decimal places.
Hence, find $x$x, correct to one decimal place.