Problem number 21. Zoran builds towers from three types of blocks. The heights of three of the towers are shown in the picture. What is the height of the fourth tower? 12, 13, 14, 16, or 17? To find the height of the last tower, we need to find the height of the triangle and the height of the square and add them together. So let's look at the towers one at a time. Here is the first tower. Let's compare it to the third tower. We need to add the triangle to make them the same height. That means that 15 plus the height of the triangle equals 20. So the triangle has a height of 5. Let's keep that in mind and take a look at the second tower. We're going to do something similar and I'm just going to put the square under the tower because as long as we have the same blocks, it doesn't matter what order they're in to get the same height. So 13 plus the height of the square will be 20, which means that the height of the square is 7. Now we know that the height of the triangle is 5 and the height of the square is 7. We can add those together to get 12. So the height of the fourth tower is A, 12.

tower heights

block types

triangle height

square height

fourth tower