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:
D.) the initial height of the roller coaster
Step-by-step explanation:
#5) 7.065 sq. ft.
#6) 36 ft
#7) 200.96 sq. ft.
#8) 176.625 sq. ft.
Explanation
#5) Converting 18 inches to feet, 18/12 = 1.5. The area of the circle would be given by A=3.14(1.5)² = 3.14(2.25) = 7.065 sq. ft.
#6) The radius is 18 inches, so the diameter is twice that: 18*2 = 36 inches. Converting this to feet, we have 36/12 = 3 feet. Each stone is 3 feet across. Laying 12 of them against each other would give us a total length of 12*3 = 36 feet.
#7) The radius of the entire mirror with frame is 20/2 = 10. The area of the entire mirror with frame is A=3.14(10²) = 3.14(100) = 314 in².
The area of the mirror without the frame is A=3.14(6²) = 3.14(36) = 113.04 in².
The difference between the two will give the area of the frame:
314-113.04 = 200.96 in²
#8) The area of the circular region is given by A=3.14(7.5²) = 176.625 ft²
Answer:a: y=4.5+0.75x
B: y=2.5+1.25x
C: 7.5
Step-by-step explanation:
