Answer:
0.67 cm/s
Step-by-step explanation:
The area of a square is given by :
....(1)
Where
x is the side of a square

Differentiating equation (1) wrt t.

When A = 81cm², the side of the square, x = 9 cm
Put all the values,

So, the length of the side of a square is changing at the rate of 0.67 cm/s.
Answer:
5.497787144 miles
Step-by-step explanation:
Remember that circumference of a circle can be calculated with:

r=radius
We also know that the radius is just a half of the diameter.
So, the radius of the track is (1/2)/2=1/4 miles
Now, use the circumference of a circle formula to find how much she runs in 1 lap.

Simplify

This is how much she runs in 1 lap.
Multiply by 3.5 for 3 and a half laps.

The answer is around 5.497787144 miles.
Answer:
69.993
Step-by-step explanation:
Using the percentage error formula:
Percentage error = (true - measured value / true measurement ) * 100%
1% error in measurement
1% of 69.3
0.01 * 69.3 = 0.693
True measurement = error in measurement + measured value
True measurement = 0.693 + 69.3
Actual measurement = 69.993
Hence, actual measurement = 69.993.