Answer :
Let's assume the opposite of the statement i.e., 3 + √5 is a rational number.


Since, a, b and 3 are integers. So,

Here, it contradicts that √5 is an irrational number.
because of the wrong assumption that 3 + √5 is a rational number.

Hence, 3 + √5 is an irrational number.
First one:
cos(A)=AC/AB=3/4.24
cos(B)=BC/AB=3/4.24
Cos(A)/cos(B)=AC/AB / (BC/AB) = AC/AB * AB/BC = AC/BC=3/3=1
Second one:
To solve this problem, we have to ASSUME AFE is a straight line, i.e. angle EFB is 90 degrees. (this is not explicitly given).
If that's the case, AE is a transversal of parallel lines AB and DE.
And Angle A is congruent to angle E (alternate interior angles).
Therefore sin(A)=sin(E)=0.5
Answer:
B. 252
Step-by-step explanation:
To find the answer, you have to use the formula to calculate the number of combinations as in this case, the order in which the objects are selected doesn't matter:
nCr=n!/r!(n-r)!
n= number of sample points: 10
r= number of sample points in each combination: 5
10C5= 10!/5!(10-5)!
10C5= 10!/5!*5!
10C5= 252
According to this, the answer is that you have 252 different ways to choose your school lunch.