20, 16, and ___.

Question

What is the missing number to make an acute triangle

Answer 1

The missing number would need to be greater than the sum of the other two sides in order to form an acute triangle.

If we take 20 and 16 as two sides, the missing number would need to be less than 36 in order to make an acute triangle.

Let's try adding a number that is less than 36 but greater than the sum of 20 and 16, let's try with 18:

20 + 16 + 18 = 54

Since 54 is greater than 36, the missing number 18 would help to make an acute triangle with side lengths 20, 16, and 18.