Is the correspondence between the perimeter set L and the area set a of a square a function and why? Is the correspondence between the perimeter set and the area set of a triangle a function and why?

Is the correspondence between the perimeter set L and the area set a of a square a function and why? Is the correspondence between the perimeter set and the area set of a triangle a function and why?

The correspondence between the set of perimeter L and the set of area a of a square is a function
Because area = (perimeter / 4) ^ 2,
For any element in perimeter set L, only one element in area set a corresponds to it
The correspondence between the perimeter set and the area set of a triangle,
It's not a function
Because for the same perimeter, the value of area is not unique

The relationship between column variables is not a function, but a. the width of a rectangle is fixed, its length and area B. the perimeter and area of a square C. someone's age and weight
D. The volume and radius of the ball

A. If the width of a rectangle is fixed, when the length is given a definite value, the area can also be given a definite value. The relationship between length and area is a function
B. When the perimeter of a square is determined, its side length is also determined, so the area is determined. Therefore, the perimeter and area are a function
C. There is no necessary relationship between age and weight. People of the same age may have different weight, and people of different ages may have the same weight. There is no functional relationship between them
D when the radius of the ball is determined, the size and volume of the ball will be determined. Therefore, the volume and radius of the ball are functions
Answer: C

Isosceles triangle bottom length 10, waist length 13, find the height of the waist
See clearly! It's the height of the waist!
60 times 2 divided by 13 = 60 / 13? I'm going crazy~

I didn't see it clearly,
Now it's changed
Half of the bottom = 5, square of the height = 13 ^ 2-5 ^ 2 = 144
Bottom height = 12
Area = 1 / 2 * 10 * 12 = 1 / 2 * 13 * waist height
So waist height = 120 / 13

If the ratio of the waist length to the base length of an isosceles triangle is 13:10 and the height of the base is 60, then the area of the triangle is

Let the base be 10x and the waist be 13X
Square of (5x) + square of root 60 = (13X), the solution is x = (root 60) / 12
So the bottom is five times root 60 / 6
Area s = root 60 × 5 times root 60 / 12 = 25
The one upstairs did the wrong thing