3D Trigonometry

Grade A/ A* questions often involve you finding distances and angles in 3 dimensional objects.  The key to these questions is to identify and draw the relevant 2 dimensional triangle.

Sometimes you are asked to find the angle between two planes.  A plane is a flat surface.  Draw a straight line down the middle of each plane - the angle between them is the one you want to calculate.  Join up the two lines to form a triangle and you have a standard trigonometry question.  If there is a right-angle, you can use SOHCAHTOA to solve it.

Here’s the worksheet we did in class.  The answers are below.
Cubiod   a) 3.6cm b) 5.4cm c) 6.2cm d) 33.7^o

Pyramid   a) 2.1cm   b) 3.4cm  c)  58.0^o   d) 66.1^o

Click here for further explanation, examples and more questions.