Open Middle: Triangle Angles

[size=150]Source: [url=https://www.openmiddle.com/]Open Middle[/url]
Problem by [url=https://twitter.com/aa_henderson]Ashley Henderson[/url] [/size]
Source: Open Middle Problem by Ashley Henderson

Use the drop-down lists to create angles of different sizes so that a triangle is formed. Be sure not to repeat digits!

Try to create another triangle that's different from the one above (still without repeating digits).

Try to create another triangle that's different from the two you made above (still without repeating digits).

What must be true about the measures of the three interior angles of a triangle? Explain.