Ravi's kite string forms a straight line given by (x−1)/2 = (y−2)/−1 = z/2. If the ground is the xy-plane, what is the sine of the angle the string makes with the ground?

Ravi's kite string forms a straight line given by (x−1)/2 = (y−2)/−1 = z/2. If the ground is the xy-plane, what is the sine of the angle the string makes with the ground?

• A. 2/3
• B. 1/3
• C. 4/9
• D. 1/2

Answer: A) 2/3

Explanation: Ground is xy-plane, normal is z-axis (0, 0, 1). Line DRs are 2, −1, 2. Angle with plane has sin θ = |al + bm + c*n| / (mag1 * mag2). sin θ = |(2)(0) + (−1)(0) + (2)(1)| / (3 * 1) = 2/3.