Answer:
x > 2/3
Step-by-step explanation:
-4(3x - 5) < 2(3x + 4)
Divide both sides by 2.
-2(3x - 5) < 3x + 4
Distribute on the left side.
-6x + 10 < 3x + 4
Subtract 3x from both sides.
-9x + 10 < 4
Subtract 10 from both sides.
-9x < - 6
Divide both sides by -9. Remember that when you divide both sides of an inequality by a negative number, the inequality sign changes direction.
x > (-6)/(-9)
x > 6/9
x > 2/3
<span>The point of concurrency of the three medians of a triangle is called the orthocenter of the triangle.</span>
Answer:
Step-by-step explanation:
AB = 6 cm, AC = 12 cm, CD = ?
In triangle ABC, ∠CBA = 90°, therefore in triangle BCD ∠CBD = 90° also.
Since ∠BDC = 55°, ∠CBD = 90°, and there are 180 degrees in a triangle, we know ∠DCB = 180 - 55 - 90 = 35°
In order to find ∠BCA, use the law of sines:
sin(∠BCA)/BA = sin(∠CBA)/CA
sin(∠BCA)/6 cm = sin(90)/12 cm
sin(∠BCA) = 6*(1)/12 = 0.5
∠BCA = arcsin(0.5) = 30° or 150°
We know the sum of all angles in a triangle must be 180°, so we choose the value 30° for ∠BCA
Now add ∠BCA (30°) to ∠DCB = 35° to find ∠DCA.
∠DCA = 30 + 35 = 65°
Since triangle DCA has 180°, we know ∠CAD = 180 - ∠DCA - ∠ADC = 180 - 65 - 55 = 60°
In triangle DCA we now have all three angles and one side, so we can use the law of sines to find the length of DC.
12cm/sin(∠ADC) = DC/sin(∠DCA)
12cm/sin(55°) = DC/sin(60°)
DC = 12cm*sin(60°)/sin(55°)
DC = 12.686 cm
