Which of the following equations represents a quadratic function?
2 answers:
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Answer:
9.6 square inches.
Step-by-step explanation:
We are given that ΔBAC is similar to ΔEDF, and that the area of ΔBAC is 15 inches. And we want to determine the area of ΔDEF.
First, find the scale factor <em>k</em> from ΔBAC to ΔDEF:
Solve for the scale factor <em>k: </em>
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Recall that to scale areas, we square the scale factor.
In other words, since the scale factor for sides from ΔBAC to ΔDEF is 4/5, the scale factor for its area will be (4/5)² or 16/25.
Hence, the area of ΔEDF is:
In conclusion, the area of ΔEDF is 9.6 square inches.
Answer:
Hence, option: B is correct (11.02 seconds)
Step-by-step explanation:
Spencer hits a tennis ball past his opponent. The height of the tennis ball, in feet, is modeled by the equation h(t) = –0.075t2 + 0.6t + 2.5, where t is the time since the tennis ball was hit, measured in seconds.
Now we are asked:
How long does it take for the ball to reach the ground?
i.e. we have to find the value of t such that height is zero i.e. h(t)=0.
or
i.e. we need to find the roots of the above quadratic equation.
on solving the equation we get two roots as:
t≈ -3.02377 and t≈11.0238
As time can't be negative; hence we will consider the value of t as t≈11.0238.
Hence it takes 11.02 seconds for the ball to reach the ground.
Hence option B is correct (11.02 seconds).