Good afternoon, dear guests and subscribers of my channel!
Today I would like to digress a little from the construction topic and devote the topic to the "queen of sciences" - mathematics.
As far as you know, I really love mathematics and geometry, so some posts are dedicated to these particular disciplines.
I wrote earlier that my sister worked as a teacher for 20 years in Russia and her fate decreed that she left the country - with her husband and children she left for America two years ago, settling there in one of schools.
She has successfully passed exams and tests for her knowledge of the English language - now she teaches mathematics in primary school. Plus, she gives tutoring lessons, providing additional income for her family.
And, of course, she knows that I also love mathematics, so she sometimes sends me interesting "American" problems. Earlier this year, I wrote about how their school decided to test US teachers, then I laid out a page from the next test in one of my articles "Calculate the perimeter of the figure below":
It seemed strange that the task was given in centimeters, instead of inches familiar to Americans. But, the task is the task ...
As a warm-up, try to solve :-)))
Now, the question is much more complicated, you can say with an "asterisk":
So, the task is as follows:
Below, there are 4 squares with sides equal to 12,9,7 and 3, respectively. Find the difference between gray and black square?
There is also a postscript that the ruler cannot be used ...
We see that the presented squares intersect and the white areas are common for two neighboring ones, this is the moment that haunts the solution :-)))
The test consists of 7 questions and the total time allotted for solving all questions is 1 hour. 20 minutes. All tasks are solved very quickly (no more than 5 minutes for each), but everything except this one - except for task # 6.
Larger photo:
I sat on this task for about 40-50 minutes to understand the solution algorithm. Do not judge strictly, it was very difficult for me.
That's all, if you want to pass the time, please... try to solve... then do not peep in response below :-)))
Decision:
Σser. = 12 * 12 + 7 * 7 - Σwhite.
Σcher. = 9 * 9 + 3 * 3 - Σwhite.
Σser. - Σcher. = (12 * 12 + 7 * 7-Σwhite) - (9 * 9 + 3 * 3 - Σwhite)
Σser. - Σcher. = 144 + 49 -Σwhite. - 81 - 9 + Σwhite.
Σser. - Σcher. = 193 - 90
Σser. - Σcher. = 103
Answer = 103
I hope you enjoyed the article.
Good luck and good!
P.S.
Below, I offer several interesting articles of mine on the topic of applied geometry.
Focuses of applied geometry: 3 cool ways to find out the height of an object while on the ground (example photos)
Trigonometry in life: The carpenter taught how to quickly mark any angles using the "yellow" square: 10 °, 20 °, 30 °, 40 °, etc.
Trigonometry in life: “Just one simple task baffles almost all roofers,” said the foreman. Roof geometry