Let's pick one person at random and call it the 'first'.
That person shakes hands with 29 other classmates.
Take another person different from the first, we'll call him the 'second'. Since he has already shaken hands with the first, he shakes hands with 28 other classmates.
The 'third' person will likewise shake hands with 27 other classmates, and so on.
Hence, the total number of handshakes is 29+28+27+...+2+1 = 29*30/2=435 handshakes
Answer:
m∡A = 41.4°
m∡B = 48.6°
m∡C = 90°
a = 3
b = 9
c = 12
Step-by-step explanation:
to find the length of side 'a' I used the Pythagorean Theorem to get:
a² + 9² = 12²
a² + 81 = 144
a² = 63
a =
which equals 
which is 3
to find m∡B I found the arcsin(B) = 9/12 to get 48.6
to find m∡A I subtracted the sum of 90 + 48.6 from 180°
For this case we can model the problem as a rectangle triangle.
We know:
Length of the sides of the triangle
We want to know:
Length of the hypotenuse
Using the Pythagorean theorem we have:

Rewriting the expression we have:

Then, the distance that he would have saved if he travels directly is:
Answer:
he would have saved:
1.8 miles