In a far, far away mathematical kingdom there lived three inseparable friends: Ruler, Triangle and Compass.
They dwelt in the expanses of the land of Mathematics, in an old castle-pencil case. There were many inhabitants in this country: various geometric shapes, numerals, all arithmetic operations, and notebooks. There were many of them, but they lived harmoniously and always rushed to help one another, although they did like to argue amongst themselves about who was the most important.
And so one day our friends decided to visit Square for tea, who lived as their neighbour.
Square lived in a new, recently built palace. The friends were so impressed by the construction that they too wanted to build themselves a new and spacious house, as their old castle was increasingly falling into disrepair: the corners had become crooked, and the roof was about to collapse.
At a home meeting the friends divided up the responsibilities, agreeing on who would be responsible for what during construction. Ruler volunteered to build the walls, Compass – the roof, and Triangle was given the windows and doors. All together with redoubled effort they set about the construction.
But it was not all so simple! When the construction was at its final stage, the friends noticed – the house had turned out crooked. They would have needed to calculate everything down to the smallest detail again, but the friends, having started to work out who and where had made the mistake, who amongst them did not know the rules of calculations in house design, had a quarrel. And they dispersed, tired and upset, to their own sections of the castle-pencil case.
And in the morning Protractor, Notebook and Pencil came to help them from the same mathematical kingdom. Having made all the measurements and verified the correctness of the angles, Pencil with the help of Protractor carried out all the calculations and computations, sketched out a construction plan in the notebook.
Compass would now be responsible for all dimensions down to the millimetre, Ruler builds the walls and roof, and Triangle is responsible for the correctness of all the angles of the house.
Heeding the advice of their mathematical friends, the drawing instruments built a new straight and beautiful house. It turned out to be of the correct shape, with new technical results. From those times onwards in the kingdom of Mathematics, they build and make all calculations only together!
