Answer:
213
Step-by-step explanation:
213
I do not understand why there are two decimal places.
But either ways if you are asking for :
0.0000489 then it is 4.89*10⁻⁵
0.489 then it is 4.89*10⁻¹
The trick is to count the zeroes to the first actual significant number you see and then write the number you counted with a negative sign for your power.
I hope this helps!
Answer:

Step-by-step explanation:
<em>m∠</em>2 and <em>m∠</em>1 are congruent by the Corresponding Angles Theorem; we set both expressions equal to each other:
[80 - x]° = [90 - 2x]°
+ x° + x°
______________
80° = [90 - x]°
-90° - 90°
__________
−10° = [−x]°

I am joyous to assist you anytime.
0/2=0 because anything divided by zero is zero.