Science Homework Help

Captain Picard is on Planet X and observes Warf and Geordie aboard the Enterprise spaceship traveling to the left (negative x-direction) at 0.80c. At the same time, he observes a Klingon spaceship approaching the planet (negative y-direction) at 0.35c. Determine the magnitude of the speed of the Klingon spaceship as observed by Warf and Geordie aboard the Enterprise.