Answer:
225
Step-by-step explanation:
Using the basic components of summation ∑
∑n = 
n(n + 1) and ∑1 = n
Thus
∑ (2n - 1) ← for n = 1 to 15
= ∑2n - ∑1
= 2∑n - ∑1
= 2 ( n(n + 1)) - n
= n(n + 1) - n ← Evaluate for n = 15 ( the upper value )
= 15 × 16 - 15
= 240 - 15
= 225
Ah usatestprep ok 90% of awnsers are C so pick C
You need to use the Pythagorean theory. a² + b² = c². So you would end up with 10²+10²=c². So, 10²=100, therefore you would end up with 200=c². In order to find the length of the hypotenuse, you need to find C. To do this, you need to undo the square and find the square root of 200 and C. So, you would get √200=√c² which would equal 14.1 inches. Then, if needed to check the answer, plug the 10,10,and 14.1 back into the a²+b²=c² and it should make the statement true.
280*3= 840
3 journals is about 840 grams
7 because a(one side)= 1/sqrt2 * hypotenuse (7*sqrt2) THis equals 7
