PLZ HELP

First drop down is 90 or 180

second drop down is:
1 and 2
1 and 4
2 and 3
3 and 4

third drop down is 1 or 4

First drop down is 180°, second drop down is 1 and 4, third drop down is 1.

Solution:

Data in the given image:

2, 3 and 4 are interior angles of the triangle.

1 is the exterior angle of the triangle.

Triangle sum property:

Sum of the interior angles of the triangle are supplementary.

By the triangle sum property,

The sum of the measures of angles 2, 3 and 4 is supplementary (180°).

m∠2 + m∠3 + m∠4 = 180° – – – (1)

The sum of the measures of angles 4 and 1 is 180°.

Because they form a linear pair.

m∠1 + m∠4 = 180°  – – – (2)

Using the substitution property, equate (1) and (2).

m∠2 + m∠3 + m∠4 = m∠1 + m∠4

Then by the property of equality, subtract m∠4 on both sides, we get

m∠2 + m∠3 + m∠4 – m∠4 = m∠1 + m∠4 – m∠4

m∠2 + m∠3 = m∠1

Hence first drop down is 180°, second drop down is 1 and 4, third drop down is 1.