Answer:
66
Step-by-step explanation:
If there are <em>n</em> students, then the number of pairs is 
.
With 12 students, 
pairs can be formed.
The reason the formula works is this: Each of the 12 students can be paired with 11 other students (no student is paired with him/her self). But counting 12 x 11 = 132 counts each pair <u>twice</u>. Example: student A can be paired with student B,..., student B can be paired with student A. The pair was counted two times.
See the attached image that shows pairings of 5 students. There are
5(5 - 1)/2 = 5(4)/2 = 10 pairs.
Answer:
7 feet long
Step-by-step explanation:
This set up will give a right angle triangle where;
Length of the ladder is the hypotenuse = x
The distance of the ladder to the house is the adjacent = 3 feet
Angle of elevation theta = 72 degrees
Using the CAH in trigonometry identity;
cos theta = adjacent/hypotenuse
cos 72 = 3/hyp
hyp = 3/cos72
hyp = 3/0.4258
hyp = 7.05 feet
Hence the ladder is approximately 7 feet long
Congruent. In other words, the angle on the inside- if that makes sense
Answer:
(2,4).
Step-by-step explanation:
Graph of y = f(-x).
The values of x in f(-x) assume the values of -x in f(x).
For example, f(-2) in f(x) is f(2) in f(-x), and f(2) in f(x) is f(-2) in f(-x).
b) Write down the coordinates of the maximum point of the graph of y = f(-x).
In f(x), we have that x = -2. So in f(-x), it will be x = 2. y remains unchanged. So
(2,4).
