The high school courtesy club bought red and black ink pens for Teacher Appreciation Day. The club bought 75 pens in all. Each b
1 answer:
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1)
∠BAC = ∠NAC - ∠NAB = 144 - 68 = 76⁰
AB = 370 m
AC = 510 m
To find BC we can use cosine law.
a² = b² + c² -2bc*cos A
|BC|² = |AC|²+|AB|² - 2|AC|*|AB|*cos(∠BAC)
|BC|² = 510²+370² - 2*510*370*cos(∠76⁰) =
|BC| ≈ 553 m
2)
To find ∠ACB, we are going to use law of sine.
sin(∠BAC)/|BC| = sin(∠ACB)/|AB|
sin(76⁰)/553 m = sin(∠ACB)/370 m
sin(∠ACB)=(370*sin(76⁰))/553 =0.6492
∠ACB = 40.48⁰≈ 40⁰
3)
∠BAC = 76⁰
∠ACB = 40⁰
∠CBA = 180-(76+40) = 64⁰
Bearing C from B =360⁰- 64⁰-(180-68) = 184⁰
4)
Shortest distance from A to BC is height (h) from A to BC.
We know that area of the triangle
A= (1/2)|AB|*|AC|* sin(∠BAC) =(1/2)*370*510*sin(76⁰).
Also, area the same triangle
A= (1/2)|BC|*h = (1/2)*553*h.
So, we can write
(1/2)*370*510*sin(76⁰) =(1/2)*553*h
370*510*sin(76⁰) =553*h
h= 370*510*sin(76⁰) / 553= 331 m
h=331 m
Answer: After 7 years the number of birds of species A and B are same. and the number of birds during that year will be 140.
Step-by-step explanation:
Given: Sharon is conducting research on two species of birds at a bird sanctuary.
The number of birds of species A is represented by the equation below,where S represents the number of birds, x years after beginning her research.
The number of birds of species B is represented by the equation below,where S represents the number of birds, x years after beginning her research.
To plot the above function, first find points by which they are passing.
For species A, At x=0 ,
At x=2 ,
Similarly find more points and plot curve on graph.
For species A, At x=0 ,
At x=2 ,
Plot a line with the help of these two points.
Now, from the graph the intersection of curve (for A) and line (for B) is at (7,140) which tells that After 7 years the number of birds of species A and B are same. and the number of birds during that year will be 140.
Answer: 1) The best estimate for the average cost of tuition at a 4-year institution starting in 2020 =$ 31524.31
2) The slope of regression line b=937.97 represents the rate of change of average annual cost of tuition at 4-year institutions (y) from 2003 to 2010(x). Here,average annual cost of tuition at 4-year institutions is dependent on school years .
Step-by-step explanation:
1) For the given situation we need to find linear regression equation Y=a+bX for the given situation.
Let x be the number of years starting with 2003 to 2010.
i.e. n=8
and y be the average annual cost of tuition at 4-year institutions from 2003 to 2010.
With reference to table we get
By using above values find a and b for Y=a+bX, where b is the slope of regression line.
and
∴ To find average cost of tuition at a 4-year institution starting in 2020.(as n becomes 18 for year 2020 if starts from 2003 ⇒X=18)
So, Y= 14640.85 + 937.97×18 = 31524.31
∴The best estimate for the average cost of tuition at a 4-year institution starting in 2020 = $31524.31
