Calculating lengths and heights

This task is about using trigonometry to find missing lengths.
Use trigonometry to solve the following problems.
 
a)
Teresa took the ski lift 4000 metres to the top of Mount Herbert, at an angle of 40º.   
Diagram of height to ski lifts as trigonometric problem  [Not drawn to scale]
 
Calculate x, the height of Mount Herbert. Show all your working in your calculation.
 
 
x = ________ metres
 
b)
Daniel's toy boat travelled 5 metres downstream at an angle of 55° before it reached the other side of the river.   
Diagram of width of river as trigonometric problem[Not drawn to scale]
 
Calculate y the width of the river. Show all your working in your calculation.
 
 
y = ________ metres
 
c)
A penguin slid 25 metres down an iceberg at an angle of 30º until it reached the water.   
Diagram of penguins slide as trigonometric problem   [Not drawn to scale]
 
Calculate z the height of the iceberg above the water. Show all your working in your calculation.
 
 
z = ________ metres