The exterior angle at the intersection of the tangent and secant has a measure that is half the difference between the intercepted arcs.
... ((10x+20) -80)/2 = 2x+15
... 5x -30 = 2x +15
... 3x = 45
... x = 15
So, the unknown arc to the right has measure
.. 10x + 20 = 10·15 +20 = 170
And the arcs of the circle total 360°.
... 80 + z + 170 = 360
... z = 360 - 250 = 110 . . . subtract 250 from both sides
The appropriate choice for the value of z is
... B. 110
Answer:
-9 is your answer for b.
Step-by-step explanation:
Note the equal sign, what you do to one side, you do to the other. Also note the rule that if you have a positive sign & a negative sign next to each other, the resulting sign would be negative:
b + (-17) = -26
b - 17 = -26
Isolate the variable (b). Add 17 to both sides:
b - 17 (+17) = -26 (+17)
b = -26 + 17
Simplify:
b = -26 + 17
b = -9
-9 is your answer for b.
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Remember the rules:
Addition sign + Positive number = Add (Ex: 7 + 7 = 14)
Addition sign + Negative number = Subtract (Ex: 7 + (-7) = 7 - 7 = 0)
Subtraction sign + Positive number = Subtract (Ex: -3 + 4 = 4 - 3 = 1)
Subtraction sign + Subtraction sign = Add (Ex: 5 - (-5) = 5 + 5 = 10)
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X + y is the number of students who were surveyed.
x is the number who own a bike.
y is the number who don't.
the ratio of the ones who own a bike and the ones who were surveyed is x / (x + y)
that ratio is 7/8.
you get x / (x + y) = 7/8
multiply both sides of this equation by (x + y) to get x = (x + y) * 7/8
simplify to get x = 7/8 * x + 7/8 * y
subtract 7/8 * x from both sides of this equation to get:
1/8 * x = 7/8 * y
solve for x to get x = 7 * y
this means that the number of students who own a bike is 7 times the number of students who don't.
divide both sides of that equation by y to get x/y = 7/1.
that means that the ratio of students who own a bike to the number of students who don't is equal to 7/1.
the problem states that the difference between the number who own a bike and the number who don't is 72.
this means that x - y = 72
from the equation of x = 7 * y, replace x with 7 * y in the equation of x - y = 72 to get:
7 * y - y = 72
simplify to get 6 * y = 72
divide both sides of that equation by 6 to get y = 72/6 = 12
this means that the number of students who do not own a bike is 12.
since x = 7 * y, then x = 7 * 12 = 84.
this means that the number of students who own a bike is 84.
since the number of students is x + y, this means that the number of students who were surveyed is 84 + 12 = 96.
let's see if this is right.
96 students were surveyed.
84 own a bike and 12 don't.
the difference between the ones who own a bike and the ones who don't is 84 - 12 = 72.
the ratio of the ones who own a bike and the number surveyed is 84/96 = 7/8.
solution is 96 students were surveyed.
<span>7/10 = 0.7
hope it helps</span>
