There's an app called photomath that would be useful for these kinds of problems!
Answer:
69.81 sq. m. (rounded to 2 decimal places)
Step-by-step explanation:
The sector of a circle is "part" or "portion" of a circle. The formula for the area of a sector is:

Where
is the central angle
r is the radius
Given the figure, the arc is given as 80 degrees, but not the central angle of the shaded sector. But from geometry we know that the central angle and the intercepted arc have the same measure. So we can say:

Also, the radius of the circle shown is 10 meters, so
r = 10
Now, we substitute in formula and find our answer:

Thus,
The area of the shaded sector is 69.81 sq. meters.
The usual margin of error we strive for is a 95% probability that our estimate is within the margin. Assuming a normal distribution (and that we have a big enough sample not to worry about t tests) that corresponds to between minus and plus two standard deviations of the mean (remember the 68-95-99.7 rule). So our margin of error is plus or minus two standard deviations.
Answer: ±2%
The ratio of linear dimensions (side lengths) is the square root of the ratio of areas.
√1 : √4 = 1 : 2
The best choice is ...
B. 1:2