SOLUTION: The average sea-level in 1900 at London-bridge was 33 feet. In 1990 it was 33.08 feet. Use linear interpolation or extrapolation to find: (a) What the average sea-level was in 19

Algebra ->  Test -> SOLUTION: The average sea-level in 1900 at London-bridge was 33 feet. In 1990 it was 33.08 feet. Use linear interpolation or extrapolation to find: (a) What the average sea-level was in 19      Log On


   

Question 1052269: The average sea-level in 1900 at London-bridge was 33 feet. In 1990 it was 33.08 feet. Use linear interpolation or extrapolation to find:
(a) What the average sea-level was in 1961. (in feet)
(b) In what year the average sea-level will be 35 feet.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = number of years after 1900
Calll 1900 +x+=+0+
Then 1990 is +x+=+90+
Let +y+ = height in feet
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You are gven the points
( 0, 33 )
( 90, 33.08 )
Use general point-slope formula
+%28+y+-+33+%29+%2F+%28+x+-+0+%29+=+%28+33.08+-+33+%29+%2F+%28+90+-+0+%29+
Multiply both sides by +90x+
+90%2A%28+y+-+33+%29+=+.08x+
+90y+-+2970+=+.08x+
+90y+=+.08x+%2B+2970+
+y+=+.000889x+%2B+33+ ( equation to use )
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Check:
does it go through ( 90, 33.08 ) ?
+33.08+=+.000889%2A90+%2B+33+
+33.08+=+.08001+%2B+33+
+33.08+=+33.08001+
close enough
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(a)
+x+=+61%0D%0A%7B%7B%7B+y+=+.000889x+%2B+33+
+y+=+.000889%2A61+%2B+33+
+y+=+.0542+%2B+33+
+y+=+33.0542+
In 1961, the height will be 33.05 ft
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(b)
+y+=+35+
+35+=+.000889%2Ax+%2B+33+
+.000889x+=+2+
+x+=+2250+
+1900+%2B+2250+=+4150+
The height will be 35 ft in 4150
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check my math