It's a trap. The drawing is misleading. If the left triangle already has 60° and 40° then only 80° remains. Meaning there's no right angle. The vertical line should be leaning to the left slightly. The correct answer is 135°.
If a tweet (or similar) makes a statement of fact, either mark it as "satire" in the body or provide the original source link backing up the statement (see rule 6)
It's a trap. The drawing is misleading. If the left triangle already has 60° and 40° then only 80° remains. Meaning there's no right angle. The vertical line should be leaning to the left slightly. The correct answer is 135°.