A meteoroid is traveling east through the atmosphere at 18.3 km/s while descending at a rate of 11.5 km/s. what is its speed, in km/s?

Use the Pythagorean theorem to find the magnitude of the resultant, southeast vector. A squared plus B squared equals C squared, right?

so, (south) ^2 + (east) ^2 = (southeast) ^2

(11.5) ^2 + (18.3) ^2 = (resultant) ^2

Resultant = 21.6 km/s