15000 miles long. So length times width
Idont under stand this thanks
The first thing I would do is convert that 1.2 kilograms of salt to grams; that would ensure that all the units are the same so we can perform calculations on them.
1.2kg = 1200g
Next, I would find out how many students can do the experiment with 1200g of salt, by finding it how many 25g are in 1200g (by dividing them).

That means we still have 80 students left to provide salt for (128 - 48).
Therefore, he needs an additional 80 amounts of 25g of salt.
Therefore he needs:
Answer:
A) 0.265
B) 0.0265
C) 0.837
D) 0.0837
E) 0.00265
F) 0.00837
Step-by-step explanation:
We are given;
√7 = 2.65 and √70 = 8.37
A) √0.07 can be rewritten as;
√(7 × 1/100)
Let's deal with the digits in the bracket.
Square root of 100 is 10. Thus;
√(7 × 1/100) = (1/10)√7 = (1/10) × 2.65 = 0.265
B) √0.0007
Rewrite to get;
√(7 × 1/10000)
Square root of 1/10000 is 1/100
Thus;
√(7 × 1/10000) = (1/100)√7 = (1/100) × 2.65 = 0.0265
C) √0.7
Like above;
√0.7 = √(70 × (1/100))
>> (1/10)√70 = (1/10) × 8.37 = 0.837
D) √0.007
Like above;
Rewrite to get;
√(70 × 1/10000)
Square root of 1/10000 is 1/100
Thus;
√(70 × 1/10000) = (1/100)√70 = (1/100) × 8.37 = 0.0837
E) √0.000007
Rewritten to;
√(7 × (1/1000000))
√(1/1000000) = 1/1000
Thus; √(7 × (1/1000000)) = 1/1000 × √7 = 1/1000 × 2.65 = 0.00265
F)√0.00007
Rewritten to;
√(70 × (1/1000000))
√(1/1000000) = 1/1000
Thus; √(70 × (1/1000000)) = 1/1000 × √70 = 1/1000 × 8.37 = 0.00837
The area of a circle is Pi * R^2 (or R * R).
Since we have our radius, R, we can solve.
With our given answer choices, we do not need to multiply R by Pi, instead we will square R, as that's our only option.
4.5 x 4.5 = 20.25.
Our area is now 20.25Pi.
Your answer is C.) 20.25Pi.
I hope this helps!