9514 1404 393
Answer:
7.28
Explanation:
Consider the attachment. There, we have identified a point C that makes ABC a right triangle with the right angle at C.
The Pythagorean theorem gives you the relationship between side lengths of a right triangle. The square of the hypotenuse (longest side) is equal to the sum of the squares of the other two sides.
AB² = AC² +BC²
We can count grid squares to find the lengths of AC and BC. They are 2 units and 7 units, respectively. This means ...
AB² = 2² +7²
AB² = 2·2 +7·7 = 4 +49 = 53
When we know the square, we can find what it is the square of by taking the square root. Generally, a calculator is required for this.
AB = √53 ≈ 7.2801099
When we round this number to two decimal places (the nearest hundredth), we get ...
AB ≈ 7.28 . . . units
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Additional comments
You will notice that the length AC in the diagram is the difference of the x-coordinates of points A and B. Similarly, the length BC in the diagram is the difference of y-coordinates. Then the square AB² is the sum of the squares of these differences. The length AB is the square root of that sum.
In general, this is how you find the length of a line segment from its end point coordinates.
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A little magic, perhaps: You may find that repeating the 11-digit number on the first line several times a day for a few days will help to moderate your difficulty understanding this. The numbers convey an energy that is intended to counteract the brain block that often arises when seeing a math problem.