please help me thank you

Work Shown
180 - (38+42) = 100
Another approach is to label the angles A,B,C. Let's say A and B are the two known angles and we solve for C. The inside angles of any triangle always add to 180 degrees.
A+B+C = 180
38+42+C = 180
C = 180-(38+42)
C = 100
Or
A+B+C = 180
38+42+C = 180
80+C = 180
C = 180-80
C = 100
Answer:
Step-by-step explanation:
To determine the number that belongs in the green box, we need to round the given numbers to the nearest hundredth.
Let's consider the numbers provided:
[?]°
38°
5
42°
Skip
To round a number to the nearest hundredth, we look at the digit in the thousandth place. If it is 5 or greater, we round up. If it is less than 5, we round down.
Looking at the numbers given, we can round them as follows:
To round a number to the nearest hundredth, we look at the digit in the thousandth place. If it is 5 or greater, we round up. If it is less than 5, we round down.
Looking at the numbers given, we can round them as follows:
[?]° (unknown number, so we'll calculate it later)
38° remains as it is.
5 becomes 5.00 (rounded to the nearest hundredth).
42° remains as it is.
Skip (no calculation needed).
Now, we need to determine the unknown number that belongs in the green box. To do this, we can compare the rounded numbers:
[?]° (unknown number)
38° (38.00 when rounded to the nearest hundredth)
5° (5.00 when rounded to the nearest hundredth)
42° (42.00 when rounded to the nearest hundredth)
By comparing the rounded numbers, we can see that the unknown number should be 38°, as it is the closest number to the original value of 38° when rounded to the nearest hundredth.
Therefore, the number that belongs in the green box is 38°.