i need help with both exercise 1 and exercise 4 in c language

note for exercise 4 do not use any built in function to compute the square of a number

z=(1/x^2) + (1/y^2)

Exercise 1 Create two functions, one that calculates the area of a triangle and a second one that calculates the circumference of a circle. In main, ask the user which of the two operations they wish to be carried out, i.e., if a 1 is entered then execute triangle function; if a 2 is entered then execute circle function, otherwise print Invalid input; print results from within main function Note: Use any values for base, height, and radius Exercise 4 Call-by-Reference You have to compute the following equation 1. In main ask the user to enter two values for x and y, respectively, using a single scanf function. Pass these two values to a function named squared that computes the squares of both x and y, that is, x and y? Function squared is a void function, that is, returns nothing to the caller. In main, compute the sum of their inverses and print the result