Note: This is the answer if you are talking about a triangle because you didn't specify that.
A=30°
I'm going to assume this is a triangle so if I'm wrong tell me in the comments. If it is a triangle all the angles should add up to 180 degrees. We already know that one is 90 so the other two angles have to add up to 90 (since 90+90=180). C is twice as much as A. So 1/3 of 90 is A and 2/3 of 90 is C. <em>A would be 30°</em>. In summary A=30° B=90° C=60°. Hopefully I understood your question correctly and this helped you. Also sorry it took a while to answer.
The Lesser Sooty Owl is a strictly nocturnal bird. Hides & sleeps during the day in dense foliage, between tangles of aerial roots, in all kinds of crevices, or beneath overhanging banks. Hunts in clearings and near roads, but also inside forest.