A red square is drawn in one corner of a rectangle so that it just fits under the diagonal as shown in the diagram.

If the rectangle has dimensions 10cm and 15cm find the area of the square.

Topics: Starter

How did you use this starter? Can you suggest
how teachers could present or develop this resource? Do you have any comments? It is always useful to receive
feedback and helps make this free resource even more useful for Maths teachers anywhere in the world.

Click here to enter your comments.

If you don't have the time to provide feedback we'd really appreciate it if you could give this page a score! We are constantly improving and adding to these starters so it would be really helpful to know which ones are most useful. Simply click on a button below:

Excellent, I would like to see more like this

Good, achieved the results I required

Satisfactory

Didn't really capture the interest of the students

Not for me! I wouldn't use this type of activity.

Good, achieved the results I required

Satisfactory

Didn't really capture the interest of the students

Not for me! I wouldn't use this type of activity.

This starter has scored a mean of 2.0 out of 5 based on 1 votes.

Previous Day | This starter is for | Next Day

Let the length of the square be x centimetres.

Consider the corresponding lengths of the smaller sides of the two orange triangles.

\(\frac{10-x}{x} = \frac{x}{15-x}\)

Solving this equation gives x = 6

So the area of the red square is 36cm^{2}

More Mathematics Lesson Starters

How did you use this starter? Can you suggest how teachers could present or develop this resource? Do you have any comments? It is always useful to receive feedback and helps make this free resource even more useful for Maths teachers anywhere in the world. Click here to enter your comments.

Your access to the majority of the Transum resources continues to be free but you can help support the continued growth of the website by doing your Amazon shopping using the links on this page. Below is an Amazon search box and some items chosen and recommended by Transum Mathematics to get you started.

## Numbers and the Making of UsI initially heard this book described on the Grammar Girl podcast and immediately went to find out more about it. I now have it on my Christmas present wish list and am looking forward to receiving a copy (hint!). "Caleb Everett provides a fascinating account of the development of human numeracy, from innate abilities to the complexities of agricultural and trading societies, all viewed against the general background of human cultural evolution. He successfully draws together insights from linguistics, cognitive psychology, anthropology, and archaeology in a way that is accessible to the general reader as well as to specialists." more... |