Answer:
66.0°
Step-by-step explanation:
The sum of the measures of the interior angles in a triangle is 180°.
Let "x" represent the measure of the third interior angle. We can use this to set up an equation:
84.0° + 30.0° + x = 180°
Add like terms:
114.0° + x = 180°
Subtract 114.0° from both sides:
x = 66°
The question asks for the answer to be in degrees to one decimal place, therefore:
x=66.0°