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
Answer:
x greater than or equal to 12cm^2
Step-by-step explanation:
We have that
x²<span> + 7x + c
</span><span>Group
terms that contain the same variable
</span>(x² + 7x )+ c
<span>Complete
the square. Remember to balance the equation
</span>(x² + 7x+3.5² )+ c-3.5²
Rewrite as perfect squares
(x+3.5)²+ c-3.5²
so
c-3.5² must be zero
c-3.5²=0------- c=3.5²------> c=12.25
the answer isthe value of c must be 12.25
Do you want this simplified?
Answer:
oh you do 3 - 8 witch equals -3=x minus 6 = -9
Step-by-step explanation:
hope this helps
