The speed of light in a vacuum is 2.998×108 m/s 2.998 × 10 8 m / s . Calculate its speed in miles per hour (miles/h m i l e s / h ).

The speed of light in a vacuum is 6.69 * 10⁸

Explanation:

Two magnitudes are directly proportional when increasing one quantity increases the other in the same proportion or when decreasing one quantity decreases the other in the same proportion.

The rule of three allows the resolution of problems that are related to the proportionality of three known values and a fourth value that is always an unknown. In other words, it is useful to establish the proportionality between 2 values a and b through the knowledge of a third value c in order to calculate a fourth value x. In the case of direct margins, the rule of three between a, b and c and the unknown x is:

a ⇒ b

c ⇒ x

So:

In this case, knowing that 1 meter is equal to 0.000621 miles, 1 second is equal to 0.000278 hours, the simple rule of three is applied as follows: if 1 meter is equal to 0.000621 miles, 2.998 * 10⁸ meters are equal to how many miles?

miles=186,175.8

Replacing the seconds by their equivalent in meters:

Then:

2.998*10⁸ = 669,697,122.3 ≅ 6.69 * 10⁸

The speed of light in a vacuum is 6.69 * 10⁸