Which relationship in the triangle must be true?
TE
sin(B) = sin(A)
sin(B) = cos(90 - B)
COS(B) = sin(180 - B)
COS(B) = cos(A)

Cosine stands for "complementary sine."  The sine of an angle is the cosine of the complementary angle and vice versa.  Complementary angles add to 90°.

sin(B) = cos(90 - B)

It's true for any angle, and it doesn't have much particularly to do with a triangle.

75 tickets have been sold so far.

step-by-step explanation:

in this question it is clearly mentioned that 45 children's tickets have been sold and this number is 60% of the total tickets sold.

now let's assume the total number of tickets sold be x.

then 60% of x = 45

⇒

⇒ x(.6) = 45

by dividing with .6 on both the sides of the equation

⇒ x = 75

therefore 75 tickets have been sold so far.

correct choice is b

step-by-step explanation:

when you calculate the average rate of change of a function, you are finding the slope of the secant line between the two points. for the function the average rate of change from point to point can be calculated as

to find the average rate of change from day 2 to day 10, note that at day 2, 8 houses were sold, so a(2,8) and at day 10, 2 houses were sold, so b(10,2). thus,