120 students are interviewed.
1 answer:
You might be interested in
Answer:
" Vertical angles are congruent " ⇒ 2nd answer
Step-by-step explanation:
* <em>Look to the attached figure </em>
- There are three lines intersected at point D
- We need to find the missing in step 3
∵ Line FA intersects line EC at point D
- The angles formed when two lines cross each other are called
vertical angles
- Vertical angles are congruent (vertical angles theorem)
∴ ∠ADC and ∠FDE are vertical angles
∵ Vertical angles are congruent
∴ ∠EDF ≅ ∠ADC
∴ m∠EDF ≅ m∠ADC
∵ m∠EDF = 120° ⇒ given
∵ m∠ADC = m∠ADB + m∠BDC
∴ m∠ADB + m∠BDC = 120°
∵ m∠ADB = (3x)° ⇒ given
∵ m∠BDC = (2x)° ⇒ given
∴ 3x + 2x = 120 ⇒ add like terms
∴ 5x = 120 ⇒ divide both sides by 5
∴ x = 24
Column (1) Column (2)
m∠EDF = 120° given
m∠ADB = 3 x given
m∠BDC = 2 x given
∠EDF and ∠ADC are vertical angles defin. of vert. ∠s
∠EDF is congruent to ∠ADC vertical angles are
congruent
m∠ADC = m∠ADB + m∠BDC angle add. post.
m∠EDF = m∠ADC defin. of cong.
m∠EDF = m∠ADB + m∠BDC substitution
120° = 3 x + 2 x substitution
120 = 5 x addition
x = 24 division
∴ The missing reason is " vertical angles are congruent "
- From the explanation above ∠ADC and ∠FDE are vertical
angles then they are congruent according to vertical angle
theorem
Let the cost of gasoline in the year 2000 be represented b the equation
y = a + b*x
where
x = months, counted from January
y = cost, dollars
The given data in the table is
Month: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
x, months: 1 2 3 4 5 6 7 8 9 10 11 12
y, dollars: --- --- --- --- 1.76 2.13 --- --- --- --- --- ---
When x = 5, y = 1.76.
Therefore
a + 5b = 1.76 (1)
When x = 6, y = 2.13
Therefore
a + 6b = 2.13 (2)
Subtract equation (1) from (2).
a + 6b - (a + 5b) = 2.13 - 1.76
b = 0.37
From (1), obtain
a = 1.76 - 5b
= 1.76 - 5*0.37
= -0.09
The required equation is
y = 0.37x - 0.09
The graph shows the line, with the given data for May and June.
Answer: D. y = 0.37x - 0.09
y = a + b*x
where
x = months, counted from January
y = cost, dollars
The given data in the table is
Month: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
x, months: 1 2 3 4 5 6 7 8 9 10 11 12
y, dollars: --- --- --- --- 1.76 2.13 --- --- --- --- --- ---
When x = 5, y = 1.76.
Therefore
a + 5b = 1.76 (1)
When x = 6, y = 2.13
Therefore
a + 6b = 2.13 (2)
Subtract equation (1) from (2).
a + 6b - (a + 5b) = 2.13 - 1.76
b = 0.37
From (1), obtain
a = 1.76 - 5b
= 1.76 - 5*0.37
= -0.09
The required equation is
y = 0.37x - 0.09
The graph shows the line, with the given data for May and June.
Answer: D. y = 0.37x - 0.09