B
the volume (V) of a sphere = 
πr³
We require to know the radius r to calculate the volume
using surface area of a sphere = 4πr² = 615.752
divide both sides by 4π
r² = 
= 49.0248...
take the square root of both sides
r = 
≈ 7, hence
V= × π × 7³ = 1436.76 m³ → B
Answer:
52
Step-by-step explanation:
We can write this out as an equation. Let's say that the teacher's age is x. Triple the teachers age plus the students age is 163, which can be written out as:
We want to isolate the variable, so subtract 7 from both sides. This gives us:
Finally, we divide both sides by 3, giving:
So the teacher is 52 years old.
Hope this helps!
Answer:
Step-by-step explanation:
y + 1 = -9(x + 9)
y + 1 = -9x - 81
y = -9x - 82
answer is A
Answer:
A
Step-by-step explanation:
We do the opposite.
The sum of any arithmetic sequence is the average of the first and last terms times the number of terms.
Any term in an arithmetic sequence is:
a(n)=a+d(n-1), where a=initial term, d=common difference, n=term number
So the first term is a, and the last term is a+d(n-1) so the sum can be expressed as:
s(n)(a+a+d(n-1))(n/2)
s(n)=(2a+dn-d)(n/2)
s(n)=(2an+dn^2-dn)/2
However we need to know how many terms are in the sequence.
a(n)=a+d(n-1), and we know a=3 and d=2 and a(n)=21 so
21=3+2(n-1)
18=2(n-1)
9=n-1
10=n so there are 10 terms in the sequence.
s(n)=(2an+dn^2-dn)/2, becomes, a=3, d=2, n=10
s(10)=(2*3*10+2*10^2-2*10)/2
s(10)=(60+200-20)/2
s(10)=240/2
s(10)=120
