For number 9, a triangle always adds up to 180 degrees. Since we know that the triangle is a right triangle, we can state that 3x+11+25+90=180 3x=180-11-25-90 3x=54 x=54/3 x=18 For question 10, vertical angles are equal to eachother so 10=6x+12 10-12=6x -2=6x x=-2/6=-1/3 For question 11, 45 and 3x are supplementary angles. 45+3x=180 3x=180-45 3x=135 x=135/3 x=45 Your welcome