Square roots of positive and negative numbers: First, let me introduce "square roots" and "arithmetic square roots" to you. Generally speaking, if the square of a number is equal to A, then this number is called the square root of A, which is also called the quadratic square root of A. For example, because the square of 1.2 = 1.44, 1.2 is the square root of 1.44. Because (-1.2) = 1.44 square,-1.2 is also the square root of 1.44. Regarding the square root of a number, we have the following facts: a positive number has positive and negative square roots, and the two are opposite; The square root of zero is zero; Negative numbers have no square root.
Because positive numbers have positive and negative square roots, they can be expressed as positive and negative root sign a, where a is called the root sign.
The operation of finding the square root of a number is called "square root". (where a is greater than or equal to zero)
Here is the "arithmetic square root"
The positive square root of a positive number and the square root of zero are collectively called the arithmetic square root.
(The above is the concept of square root in the first grade textbook. )
As for the area formula of triangle, that is the content of primary school, but I can provide it for you!
Triangle area = base * height ÷2
Hehe ~ I admire your studious spirit!