Um I think it would be 4 if its in the right order.
The angle supplementary to ∠3 should be the one right next to it horizontally. When you add them together they should sum up to 180 degrees, which is a straight line. Hope that helps.
The total area under the curve must equal 1. Let the value of the density curve be x. Then 10x = 1. Therefore x = 1/10 or 0.1. The correct answer is D. 0.1.
