Question

Find the missing angle.

72
Х
40°
[?]
x =
Enter the number that belongs in the green box.

Answer 1

X = [68]°

Explanation:

We know that a triangle has 180 degrees in it from the total angle measure formula:

m = 180(n-2)

Where n equals the number of sides a shape has and m is equal to the sum of interior angle measures.

m = 180(3-2)

= 180(1)

= 180

So if we know two of the angle measures, we can add them then subtract that from the total angle measure to get x.

180-(72+40) = 68

TL;DR - Add the known angle measures and subtract them from the total angle measure to get the third missing angle.

Hope this helps :)

Answer 2

x=68

Basic fact:

angles in a triangle add up to make 180 degrees

Explanation:

we know that

72+40+x=180

112+x=180

-112

x=68