Answer:
ST = 4
Step-by-step explanation:
A segment joining the midpoints of 2 sides of a triangle is half the length of the third side.
ST = PQ substitute values
- 32 + 9x = (- 5x + 28) ← multiply both sides by 2 to clear the fraction
- 64 + 18x = - 5x + 28 (add 5x to both sides )
- 64 + 23x = 28 ( add 64 to both sides )
23x = 92 ( divide both sides by 23 )
x = 4
Then
ST = - 32 + 9x = - 32 + 9(4) = - 32 + 36 = 4
9514 1404 393
Answer:
Step-by-step explanation:
To find the height at 8 seconds, evaluate the formula for t=8.
S(t) = -5t^2 +80t
S(8) = -5(8^2) +80(8) = -320 +640 = 320
The height of the rocket is 320 meters 8 seconds after takeoff.
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To find the time to 290 meters height, solve ...
S(t) = 290
290 = -5t^2 +80t
-58 = t^2 -16t . . . . . . . divide by -5
6 = t^2 -16t +64 . . . . . complete the square by adding 64
±√6 = t -8 . . . . . . . . . take the square root
t = 8 ±√6 ≈ {5.551, 10.449}
The rocket is at 290 meters height after 5.6 seconds and again after 10.4 seconds.
