This video is all about working with surds, and we’re asked to
– calculate the area
– calculate the length AC
of a right angle triangle ABC.
The height is √5 – 2, the base is √5 + 2.
The question is aimed at around grade 7+ GCSE maths, and are usually non-calculator.
These types of working with surds questions appear in all the main examination boards, including Edexcel, AQA and OCR. They are popular and, once you have the basic principles, fairly similar. Please do stop the video, try the question and compare your solution.
‘Surds' are really a way of writing ‘irrational' numbers precisely. Because the decimal places of an irrational number doesn't stop, or recur, we can use surds to write the exact number. A surd is when we can't simplify the number, or remove the square root sign so:
√4 is not a surd as it equals 2 …… √3 is a surd because it is 1.7320508…(and so on).
I hope the video helps and please do leave a comment – thanks!
If you would like to find out more try these!
Surds – ‘show that' & ‘write in the form' questions
Please do leave a comment below if you are not sure. Alternately you can view my YouTube channel and leave a comment there – I'll always try to respond as quickly as possible.
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