Home > #MTBoS, Assessment, GCSE, Pedagogy, Teaching > Forming and Solving Equations

## Forming and Solving Equations

While checking the work of a year 11 student on Friday I came across a question that could have been a great one for the higher GCSE students to practice their skills together and also their selection of which mathematics to use.

The question was to find the area of this triangle:

A great question. One that to you or I is straightforward but that would take GCSE level students and below a bit of thinking and let’s them hone their skills.

The way to tackle it is to use Pythagoras’s Theorem to form an equation, solve for x then find the area. I feel is beneficial as it combines Pythagoras’s Theorem with a decent amount of algebra then includes the find the area bit at the end.

In this case though, that wasn’t the question. There was more information on offer and the question was:

Which is still a fairly nice form and solve an equation problem.

3x + 1 + 3x + x – 1 = 56
7x = 56
x = 8
A = 0.5×7×24 = 84

There is a niceness to this question that goes beyond the question itself.  It shows us a great way of differentiating within lessons. Just be leaving out a tiny portion of the information, in this case the perimeter, we can make the question much harder. This idea is something I’ve been working on in various places. M1 questions can be made much easier by providing a diagram, for example.

Have you used questions in a similar way? If so I’d love to see them, please do get in touch.

Cross-posted to Betterqs here.

1. May 16, 2016 at 4:38 pm

I guess we could use the question according to what knowledge you would expect a class to already have been acquainted with and, therefore, how you might use it for students to use and apply Pythagoras’ theorem. However, by giving them the perimeter = 56 this might be used with students who had not met Pythagoras. There is another issue I would like to raise. This is as students solve the problem without being given the perimeter to then ask them to construct their own examples. This in turn would require them to have knowledge of Pythagorean triples which, in itself, is a fascinating area for exploration.
Regards
Mike