Question

Can the sides of a triangle have lengths 10, 19, and 20

Answer 1

Definitely can.
The sum of lengths of two sides in a triangle is greater than the third side.
Hope It Helps

Answer 2

Yes

Explanation:

A rule for any triangle is that it has to pass the Triangle Inequality Theorem, which is that the sum of the first two sides of the triangle has to be greater than the third side, in order for the lengths to be large enough to create a triangle.

In this case...
10, 19, 20
10 + 19 = 29
29 > 20

Since the sum of the first two sides of the triangle are greater than the third side it can be a triangle. So, your answer is "yes."

Hope this helps.