Answer:
2√2 km south and 2√2 km west of the volcano's crater.
Explanation:
If the scientist is at the center of the circle with the volcano's crater, then the new vent is located 45° east of due south, or 135° counterclockwise from due north.
To describe the position of the new vent relative to the crater, we can use the bearing or direction angle, which is the angle between the north direction and the line connecting the crater and the new vent, measured counterclockwise.
To find the bearing, we can draw a right triangle with the hypotenuse equal to the distance from the center of the circle to the new vent, which is also the radius of the circle, or 4 km. The opposite side of the triangle is the north-south component of the line connecting the crater and the new vent, which is equal to the radius times the sine of the angle between the line and due south. The adjacent side is the east-west component of the line, which is equal to the radius times the cosine of the angle.
Using trigonometric functions, we can calculate:
Opposite side = 4 km x sin(135°) = 4 km x (-√2/2) = -2√2 km (southward direction)
Adjacent side = 4 km x cos(135°) = 4 km x (-√2/2) = -2√2 km (westward direction)
Therefore, the new vent is located 2√2 km south and 2√2 km west of the volcano's crater. Its position relative to the crater can be described as "southwest by south."