the triangle is a right triangle, meaning that we can use the pythagorean theorem to find a hypotenuse that will satisfy both Rs. if we use 3 as the radius, we get the hypotenuse as 2 + 3 = 5, where one leg is 3 and one is 4.
Mr. Luna's travels east and west are irrelevant to the question. He drives 3 miles north, then he drives 4 more miles north. 3 + 4 = 7, so Mr. Luna ends up 7 miles north of his home.