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.
We have been given that the standard deviation of a group of 20 scores is 15 and we are asked to find variance.
Since we know variance is square of standard deviation. In order to find out the variance of the given data we have to take the square of 15.

Therefore, our variance is 225.
Answer:
1434.375
Step-by-step explanation:
If you multiply 1,800 by 25% you get 1,350
you take 1,350 and add 6.25% because the 6.25% is the tax.
Then you will get 1434.37 or 1434.40
Answer:
Angle 2=160
Angle 3=10
Step-by-step explanation:
The rhombus is made up of two isoceles triangle.
Angle 1 measures 160.
Since the triangle is a isoceles triangle, the opposite angles of the congruent sides is equal angles to each other.
So the reamaing angles in the top triangle are equal so we can use this equation
Remeber that triangle maximum degree it can hold is 180




We have two congruent triangle side they share Three sides. SSS
This means the corresponding angle of Angle 1 is Angle 2.
Angle 2=Angle 1 by CPCTC.
Angle 2=160
Angle 3 corresponds with one of the remaining congruent angles so it measures
10.
Answer:
7:13 am on Tuesday after adding the time slowly arrange properly and am sure you will get it