Answer:

Step-by-step explanation:
Let
x ----> the average depth of the resulting layers of ash and rock
we know that
To find out the average depth, divide the cubic kilometers of molten rock by the area where all the ejected material fell.
so

Convert to meters
Remember that

so

Convert to mixed number

Answer: $14.0
Step-by-step explanation:
For us to calculate this question, we have to find 20% of $17.45 and then subtract the value gotten from $17.45. This will be:
= $17.45 - (20% × $17.45)
= $17.45 - (0.2 × $17.45)
= $17.45 - $3.49
= $13.96
= $14.0 to nearest cent
Answer:
9 meter.
Step-by-step explanation: 4 1/2 meters is too short, he would have to buy 2 lengths. 4 1/2 meters is 450 cm while 9 meters is 900 cm, if he gets the 900 cm length he can just cut off the excess to use later.
Answer: 423.11 m^2
Step by step explanation:
Area of a circle formula pi*r^2
First solve the area of the big circle
3.14*21^2=1384.74 m^2
Now find the are of the smaller circle
r=21-3.5=17.5
3.14*(17.5)^2=961.63 m^2
Now we can minus the small area off the big area to get the shaded area.
1384.74-961.63=423.11 m^2
So the area of the shaded region is 423.11 m^2