The equation for this is (n-2) x 180
Replace n with the number of sides:
a. 9: (9-2) x 180 = 7 x 180 = 1,260
b. 19: (19-2) x 180 = 17 x 180 = 3,060
Answer:
285 words
Step-by-step explanation:
Answer:
Speed of boat in still water is 6km/h
Speed of current is 4km/h
Step-by-step explanation:
We know speed = distance / time
Let the speed of boat in still water be x
Let the speed of current be y
Hence the speed of boat, down stream = 
Distance downstream = 20km
Time taken = 2 hours
We have

......(1)
Speed of boat upstream = 
Distance upstream = 4
Time taken = 2
We have

...(2)
Adding (1) & (2)


Substituting in (1) we get

Answer:
1/5
Step-by-step explanation:
formula is y = kx
k is the constant of proportionality
when x is 5 y is 1
when x is 10 y is 2
so 1 = k * 5
so k = 1/5