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:
Step-by-step explanation:
This was answered in question #24217201. It's the exact same question, but you forgot to put what parts A and B are. The answers and the work are there.
Answer:
14.4 km = 1440000
Step-by-step explanation:
1 km = 1000m
14.4 km = 1000 ×14.4
=14400 m
1 m =100 cm
14400 m = 100 × 14400
= 1440000 cm
The answer in an expression is (8 + 4) x 3