Answer:
the number is 20
Step-by-step explanation:
let 'n' represent the number
2n + 9 = 49
2n = 40
n = 40/2 = 20
The sum of the first n odd numbers is n squared! So, the short answer is that the sum of the first 70 odd numbers is 70 squared, i.e. 4900.
Allow me to prove the result: odd numbers come in the form 2n-1, because 2n is always even, and the number immediately before an even number is always odd.
So, if we sum the first N odd numbers, we have

The first sum is the sum of all integers from 1 to N, which is N(N+1)/2. We want twice this sum, so we have

The second sum is simply the sum of N ones:

So, the final result is

which ends the proof.
Answer:
19.25
Step-by-step explanation:
Answer:
270
Step-by-step explanation:
Because we do not know what the side lengths are, as long as they multiply to 30m^2, it's fine
For this question, let's just say the base is 5, and the height is 6. If we triple 5, we get 15, and if we triple 6, we get 18. 15*18=270
Now what if, the sides are not 5 and 6. Will the area still be the same? Let's find out.
10*3=30 so we can say for this answer, the base is 3, and the height is 10.
10 tripled is 30, and 3 tripled is 9. 30*9=270
So as we look at these 2 answers. we can conclude that the new area, no matter the side lengths, will be 270
Hope this helpes!
Answer:
17.4076456756
Step-by-step explanation: