def triangle_area(a, b, c):
    if a + b <= c or a + c <= b or b + c <= a:
        return -1 
    s = (a + b + c)/2    
    area = (s * (s - a) * (s - b) * (s - c)) ** 0.5
    area = round(area, 2)
    return area
from typing import List
def has_close_elements(numbers: List[float], threshold: float) -> bool:
    for idx, elem in enumerate(numbers):
        for idx2, elem2 in enumerate(numbers):
            if idx != idx2:
                distance = abs(elem - elem2)
                if distance < threshold:
                    return True
    return False