Answer:
S₁₅ = 645
Step-by-step explanation:
The sum to n terms of an arithmetic sequence is
= 
[ 2a₁ + (n - 1)d ]
where a₁ is the first term and d the common difference
Using the nth term formula 
= 5n + 3 , then
a₁ = 5(1) + 3 = 5 + 3 = 8
a₂ = 5(2) + 3 = 10 + 3 = 13 , then
d = a₂ - a₁ = 13 - 8 = 5
Thus
S₁₅ = 
[ (2 × 8) + (14 × 5) ]
= 7.5( 16 + 70)
= 7.5 × 86
= 645
To form a linear pair means that when added, they equal 180 degrees.
but if they have equal measures....180/2 = 90...then they would both equal 90 degrees.....and 90 degrees is a right angle.
So ABC and CBD are both right angles
Answer:
(2) 2,640 ft
Step-by-step explanation:
I'm going to assume that in this question, you are walking 1 full circle around the reservoir. That would mean you need to calculate the circumference of the circular reservoir.
The circumference formula is:
C = ⫪d
C stands for Circumference
d stands for diameter
I will use 22/7 instead of pi, so the formula looks more like this:
C = (22/7)(d)
The diameter is 840 feet, so we will substitute the variable d with 840:
C = (22/7)(840)
You can plug this part into the calculator, but by hand, it'll look something like this:
(22/7)*840 = (22*840)/7
18,480/7 = 2.640
Hope it helps (●'◡'●)
