Why is -7 an integer but not a natural number?

Natural Numbers are basically "counting numbers". If I ask you to start counting, you'll start at 1, then 2, then 3, and so on. It doesn't include 0 or any negative numbers because you wouldn't start from -10 when asked to count.

-7 is negative so it cannot be a natural number, but it is an integer. An integer is a whole number, this means that it does not have any decimal places or fractions. However, a natural number must be a whole non-zero number and positive. This is because natural numbers are numbers found naturally in measurements or in counting. Additionally, all natural numbers are integers but not all integers are natural numbers. For example, -3 would be an integer, 9 would be an integer and a natural number, and 7.6 would be neither.

Here, It is stated that the triangle having sides 3, 5 and 6 respectively. So, we have to prove that whether the given triangle is right angled triangle or not.

For That :

We will be using the Pythagoras Theorem

According to the Pythagoras Theorem , the sum of the square of Base side and perpendicular side is equal to the square of the longest side i.e, hypotenuse.

Pythagoras Theorem :

⠀⠀⠀⠀⠀⠀

So, here the longest side is Side A of measurement 6.

So, Now

Applying Pythagoras Theorem in it, we get :

The three sides , so let's plug the values in the formula :-

If in a triangle, the square of the hypotenuse is not equal to the sum of the squares of the other two sides, then the given triangle and doesn't satisfy pythagoras theorem. Hence, Its not a right angled triangle.