A rational number can be written as the ratio of one integer to another and can be represented by a repeating or terminating decimal.
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: 15 grams
If he had 100 grams of candy bar, then 30% of that is 30 grams (since 30/100 = 30%). Cut this in half and we end up with 30/2 = 15.
Another way to find the answer is to multiply 50 and 0.30 which is the decimal form of 30%. So we have 50*0.30 = 15 which is the same answer.
Step-by-step explanation:
When the car stops, the speed is zero.
When S = 0, -10t + 45 = 0, t = 4.5.
Hence it will take 4.5 seconds for the car to stop.
