Three circular gears with radius A = 5 cm, B = 2 cm and C = 6 cm are shown.

If <CAB = 37o, how long would the arm need to be that connects the centre of gear A to the centre of gear C?

1 answer

To find the length of the arm that connects the center of gear A to the center of gear C, we can use the law of cosines.

Let's label the length of the arm as x.

According to the law of cosines, we have:

x^2 = A^2 + C^2 - 2AC*cos(<CAB)

where A = 5 cm, C = 6 cm, and <CAB = 37 degrees.

x^2 = (5 cm)^2 + (6 cm)^2 - 2(5 cm)(6 cm)*cos(37 degrees)

x^2 = 25 cm^2 + 36 cm^2 - 2(30 cm^2)*cos(37 degrees)

x^2 = 25 cm^2 + 36 cm^2 - 60 cm^2*cos(37 degrees)

x^2 = 25 cm^2 + 36 cm^2 - 60 cm^2*cos(37 degrees)

x^2 = 25 cm^2 + 36 cm^2 - 60 cm^2*cos(37 degrees)

x^2 = 25 cm^2 + 36 cm^2 - 60 cm^2*(0.7986)

x^2 = 25 cm^2 + 36 cm^2 - 47.916 cm^2

x^2 = 13.084 cm^2

Taking the square root of both sides, we have:

x = √(13.084 cm^2)

x ≈ 3.62 cm

Therefore, the length of the arm that connects the center of gear A to the center of gear C is approximately 3.62 cm.