Can someone help me?
1 answer:
Answer:
Step-by-step explanation:
To start calculating, we first need to make some proof.
Firstly, since AB = AC, we know that ΔABC is isosceles, which means that ∠ABC = ∠ACB.
Now, looking only to ΔBDE and ΔCDF, we can see that they are similar, because the two of its angles are congruent:
∠BED=∠CFD
∠DBE=∠DCF
To make it easier to visualize which are the corresponding vertexes, we can draw them like this:
And we need to remember that BC is 24, so:
BD+CD=24
Since the triangles are similar, their corresponding sides have constant ratio, which we can calculate from the corresponding sides DE and CF:
This ratio is the same for the other corresponding sides, so we can apply that for BD and CD:
Thus, the measure of CF is approximately 13, alternative D.
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Answer:
a.) the probability that both the ball drawn are black =
b.) Sum of all the probabilities =
Step-by-step explanation:
a) two balls are drawn at random .
total number of balls = 10
number of black balls = 5
number of white balls = 5.
the number of ways two balls can be drawn =
the number of ways two black balls can be drawn =
the probability that both the ball drawn are black =
b) probability that First draw of two black balls =
probability that first draw is of two white balls is and second draw is of
two black balls =
Probability that first two draws are of white balls and the third draw is of
two black balls =
This is a geometric sequence and the final probability will be the sum of
all such probabilities, where we can take the the sequence to be an infinite series and the first term is and the common ratio is
which is less than 1.
Sum of all the probabilities =