I can't find my functions in outlet connection.. Do know how to solve this error?

Question

public float 내각의합구하기(int 꼭짓점) {
    return 180 * (꼭짓점 - 2);
}

public float 대각선그어서생기는삼각형개수(int 꼭짓점) {
    return 꼭짓점 - 2;
}

public float 뿔의부피구하기(float 밑면 , float 높이) {
    return (밑면 * 높이) / 3;
}

I was written like this functions about 40.
I was trying to add these functions on Onclick().
But i can't find them.
What is the problem?
Help me.