7(8 + y) simplified?
1 answer:
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Answer:
D.
Step-by-step explanation:
The point-slope form of a line is given by:
The line given to us has equation; .
The slope of this line is -4. The of the line perpendicular to this line is the negative reciprocal of the slope of the given line.
Our slope of interest is therefore;
Since the point goes through (-2,7), we have .
We plug in the slope and the point into the point-slope formula to obain;
The required equation is:
Answer:
Part 1) The length of DC is
Part 2) The measures of the angles in the isosceles triangle are
The base angles are 67.4° and the vertex angle is 45.2°
Step-by-step explanation:
step 1
In the right triangle BDC Find the length of DC
Applying the Pythagoras Theorem
we have
substitute
step 2
Find the measures of internal angles in the isosceles triangle ABC
we know that
∠DAC=∠DCA ------> base angles
∠ADC ------> vertex angle
<em>Find the measure of angle DCA</em>
In the right triangle BDC
sin(∠DCA)=BD/DC
substitute the values
sin(∠DCA)=12/13
∠DCA=arcsin(12/13)=67.4°
so
∠DAC=∠DCA=67.4°
<em>Find the measure of angle ∠ADC</em>
Remember that the sum of the internal angles of a triangle must be equal to 180 degrees
so
∠DAC+∠DCA+∠ADC=180°
substitute
67.4°+67.4°+∠ADC=180°
∠ADC=180°-134.8°=45.2°