To get one hour you multiply 30 by 2 so you multiply 20 by two also
this gives you 40km per hour
Answer:
16 ft
Step-by-step explanation:
If you connect points A and C with a straight line, you will have a right triangle with hypotenuse AC (radius), shorter leg 1/2 of CD and the longer leg 1/2 of AB.
AC = radius = 10 ft
1/2 CD = 1/2 of 12 = 6 ft
So we can use Pythagoras' Theorem to find the length of the longer leg of the right triangle:
6² + b² = 10²
36 + b² = 100
b² = 100 - 36
b² = 64
b = √64 = 8
As b = 1/2 AB, then AB = 2 x b = 2 x 8 = 16 ft
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
48 is ur answer to the question