Turn on thread page Beta
 You are Here: Home >< Maths

# Trigonometry 3D watch

1. This is a topic covered in Edexcel Mathematics but im struggling to understand the concept and is confusing :/
2. (Original post by ChocoholicCox)
This is a topic covered in Edexcel Mathematics but im struggling to understand the concept and is confusing :/
If you have a specific question you're struggling it would make it easier for people to assist you.
3. This is a question which I have been given I know that for some these you have to do pythagrous aswell
4. (Original post by ChocoholicCox)
This is a question which I have been given I know that for some these you have to do pythagrous aswell
What do you need to find?
5. (Original post by ChocoholicCox)
This is a question which I have been given I know that for some these you have to do pythagrous aswell
OK, here's one way of thinking about it.

First a general point. Almost all, if not all, the 3D problems that you're going to encounter at A-level, can be looked at in terms of 2D. The only difference is that the planes you're considering may not be horizontal or vertical, but lie at an angle.

Since they're really only 2D, then all the geometry you've learnt dealing with flat shapes applies: Pythagoras, sine rule, cosine rule, opposite angles are equal, etc.

The issue is firstly identify what are the relevant planes.

So, lets look at the length y. Well it's the diagonal of the rectangle EFGH. We know what the sides of the rectangle are, because this is a cuboid - all the faces of the overall shape are at 90 degrees to each other.

The angle GFH is easy (if you're required to work that out, it's not clear from the diagram) - it lies in the same plane as that rectangle.

Now what about x. It refers to a line. We need to consider another point in addition to get a plane. So lets choose F as a fairly obvious one.
Our plane contains the triangle CFH. We know it's a right-angled triangle, as CF is vertical and FH horizontal. We also know the lengths of CF and FH now.

Hope that helps.
6. Thanks

Reply
Submit reply
Turn on thread page Beta

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 21, 2013
Today on TSR

### Predict your A-level results

How do you think you'll do?

### University open days

1. University of Bradford
University-wide Postgraduate
Wed, 25 Jul '18
2. University of Buckingham
Psychology Taster Tutorial Undergraduate
Wed, 25 Jul '18
3. Bournemouth University
Clearing Campus Visit Undergraduate
Wed, 1 Aug '18
Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.