In a far, far away mathematical kingdom there lived three inseparable friends: Ruler, Triangle, and Compass.
They lived in the vast land of Mathematics, in an old castle-pencil case. There were many inhabitants in this country: different geometric shapes, numbers, all arithmetic operations, and notebooks. There were many of them, but they lived in harmony and always rushed to help each other, although they did like to argue about who was the most important.
One day, our friends decided to visit Square for tea, who lived nearby.
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 home, since their old castle was falling into disrepair more and more: the corners were 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 got the windows and doors. Together with redoubled effort, they set about building.
But it wasn't all so simple! When construction was in its final stages, 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 figure out who made the mistake and where, who among them didn't know the rules of calculations in house design, had a quarrel. And they scattered, tired and upset, to their own sections of the castle-pencil case.
The next morning, Protractor, Notebook, and Pencil came to help them from the same mathematical kingdom. After taking all the measurements and marking the correctness of the angles, Pencil with the help of Protractor made 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 house's angles.
Heeding the advice of their mathematical friends, the drawing instruments built a new, straight and beautiful house. It turned out to be the correct shape, with new technical results. Since those times, in the kingdom of Mathematics, they build and make all calculations only together!
