Triangular sequence = n(n + 1)/2
If 630 is a triangular number, then:
n(n + 1)/2 = 630
Then n should be a positive whole number if 630 is a triangular number.
n(n + 1)/2 = 630
n(n + 1) = 2*630
n(n + 1) = 1260
n² + n = 1260
n² + n - 1260 = 0
By trial an error note that 1260 = 35 * 36
n² + n - 1260 = 0
Replace n with 36n - 35n
n² + 36n - 35n - 1260 = 0
n(n + 36) - 35(n + 36) = 0
(n + 36)(n - 35) = 0
n + 36 = 0 or n - 35 = 0
n = 0 - 36, or n = 0 + 35
n = -36, or 35
n can not be negative.
n = 35 is valid.
Since n is a positive whole number, that means 630 is a triangular number.
So the answer is True.
Answer:
the speed of the plane was 210 mph.
Step-by-step explanation:
Answer:
54 hope this helps
Step-by-step explanation:
<u>Answer:</u>
4.5 foot is needed for a unit dozen bird house
<u>Explanation:</u>
Given Tina saw ¾ foot of wooden trim is being used for first 1/6 dozen bird houses
Therefore, we can write as,4
1/6 dozen = ¾ foot
For 1 dozen bird houses, we have to use the unitary method
1/6 dozen = ¾ foot
Therefore, 1 dozen or unit dozen = 
1 dozen = ¾ * 6 = 
foot = 4.5 foot
Therefore, 4.5 foot is needed for a unit dozen bird house
2.56 times 0.03 is 0.0768 then round to hundredth is 0.08 i think
