Anonymous

=> if U is center ∠2 = ∠5 = 90 ∠1+∠3 = 90 = 5x+(3x+10) 8x = 80 x = 10 ∠1 = 5*10 = 50 ∠3 = 30+10 = 40 ∠4+∠6 = 90 = (y+7)+(3y+11) = 4y+18 y = 18 ∠4 = 18+7 = 25 ∠6 = 3*18+11 = 65

Anonymous

∠5 = 180°-4y-18° = 162°-4y = 90° (angle in a semi-circle) y = 18° ∠2 = 170°-8x = 90° (angle in a semi-circle) x = 10° ∠1 = 50° ∠2 = 90° ∠3 = 40° ∠4 = 25°

Anonymous

U is the centre of the circle 1 + 2 + 3 = 180 4+5+6 = 180 and (assuming IG is a diameter) 2 = 5 = 90 degrees so 1 + 3 = 90 and 4+6 = 90 So you can solve for x and y, and hence determine the angle sizes (x = 10 and y = 18)