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:
Try A
Step-by-step explanation:
Answer: With a variable. A variable is a letter you use in an equation , like this: 7+x=14, X is a classic one but you can use any letter u please! (In my school at least.)
All you have to do is write a positive number. let's say 4, then write a positive exponent (that's the tiny number in the right corner of the regular number) and then just write a positive exponent less than 4.
So 4 squared