If DE=4x+10, EF= 2x-1, and DF=9x-15, Find DF
1 answer:
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Answer:
AH = 1 or 4
CH = 4 or 1
Step-by-step explanation:
An altitude divides a right triangle into similar triangles. That means the sides are in proportion, so ...
AH/BH = BH/CH
AH·CH = BH²
The problem statement tells us AH + CH = AC = 5, so we can write
AH·(5 -AH) = BH²
AH·(5 -AH) = 2² = 4
This gives us the quadratic ...
AH² -5AH +4 = 0 . . . . in standard form
(AH -4)(AH -1) = 0 . . . . factored
This equation has solutions AH = 1 or 4, the values of AH that make the factors be zero. Then CH = 5-AH = 4 or 1.
Answer:
a. The sample size is approximately 97 adults
Step-by-step explanation:
The given parameters are;
The number of adults surveyed, n = 174
The lowest value of the pulse rate = 39 bpm
The highest value of the pulse rate = 111 bpm
The level of confidence used for determining the sample size = 90%
The given sample mean = 3 pm of the population mean
a. The range rule of thumb states that the standard deviation is approximately one quarter (1/4) of the range
The range = 111 bpm - 39 bpm = 72 bpm
Therefore, the standard deviation, σ = 72 bpm/4 = 18 bpm
The sample size, 'N', is given as follows;
Where;
N = The sample size
z = The confidence level, 90% (z-score at 90% = 1.645)
p·q = σ² = 18² = 324
e² = 3² = 9
Therefore the appropriate sample size, N ≈ 97 adults.