PHP algorithm exercise 8: Determine whether the given three numbers can form a right triangle

In this article "PHP Algorithm Exercise 7: Judgment Method for Implementing Geometric Sequences", I will introduce to you how to use PHP to judge geometric sequence. Interested friends can learn about it~

This article will continue to introduce you to the PHP algorithm series knowledge. As the title states, this time it will teach you how to judge whether a right triangle can be formed by given three numbers. I can be sure that it is at least 99% My friends all did this kind of math problems when they were students! ! !

So first of all, I want to introduce to you the methods of determining right triangles:

1: A triangle with an angle of 90° is a right triangle.

#2: If a² b²=c² is satisfied, then it is a right triangle with c as the hypotenuse and ab as the right side (according to the converse theorem of the Pythagorean theorem).

3: If the side opposite to a 30° internal angle of a triangle is half of a certain side, then the triangle is a right triangle with this long side as the hypotenuse.

#4: A triangle with two mutually complementary acute angles is a right triangle.

5: If you want to prove that right triangles are congruent, you can use HL. The lengths of the hypotenuses of two triangles are equal, and the lengths of one right-angled side are equal, then the two right triangles are congruent. [Theorem: Two right triangles are congruent if the hypotenuse and a right angle are equal. Abbreviated as HL]

#6: If two straight lines intersect and the products of their slopes are negative reciprocals of each other, then the two straight lines are perpendicular.

#7: In a triangle, if the midline on one side is equal to half of the side where the midline is located, then the triangle is a right triangle.

Okay, I have introduced you to so many methods of determining right triangles. I think everyone has a clue about how to use PHP to determine them.

I will go directly to the code below:

The PHP code is as follows:

<?php
$a = 5;
$b = 3;
$c = 4;
$a *= $a;
$b *= $b;
$c *= $c;
if($a + $b == $c || $a + $c == $b || $b + $c == $a){
    echo "是\n";
}
else
{
    echo "否\n";
}

The judgment result is:

是

Here In this code, we have given three numbers: 5, 3, and 4;

Then we can calculate according to the Pythagorean Theorem to see whether these three numbers meet the requirements. It is obvious: 3 squared 4 The square of is equal to the square of 5.

That is to say, the three numbers we gave can form a right triangle.

Here is a brief introduction to the PHP assignment operator*=

For example: x *= y, it means x = x * y; then $a in the above code *= $a; can represent the square of $a~

Finally, I would like to recommend the latest and most comprehensive "PHP Video Tutorial"~ Come and learn!

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