a speedboat zips by on a lake and sends a series of waves towards the dock. the frequency of the waves is 5hz. how many wave crests will pass by the dock in 8 seconds

8+10

step-by-step explanation:

you multiply 4 by 2 and 5 by 2

80° is the measure of gh

step-by-step explanation:

circle f is congruent to circle j

we have two circle with center f and j.

both circles are congruent. the radius of the circle would be equal.

see the attachment for the circle.

we are given ∠efd ≅ ∠gjh

therefore, arc (ed) = arc (gh)     (∴ circle f is congruent to circle j)

but ∠dfe=80°=arc (ed)

therefore, arc (gh) = 80°

thus, 80° is the measure of gh

answer: $53750

steps:

list the principal and interest after the n-th year:

n       principal   simple interest

1     12500     375

2     25000     750

3     37500     1125

4     50000     1500

sum: $50000     $3750

total at end of year 4: $53750