Answer:
10. 1 right 2 acute 0 obtuse angles
11. x=6
Step-by-step explanation:
10. A triangle has 3 angles.
If it is a right triangle is has 1 right angle which is 90 degrees.
90 + x+y = 180 where x and y are the other 2 angles
Subtract 90 from both sides
x+y = 90
So the 2 angles that are left can only add to 90.
An obtuse angle is greater than 90 degrees, so we cannot have an obtuse angle. Acute angles are less than 90 degrees.
A right angle is 90 degrees. If one of the angles left is 90 degrees, the other one is zero, and that does not make a triangle.
So we must have 1 right angle and 2 acute angles (no obtuse angles)
11. Since the 2 sides are the same the triangle is isosceles. That means the two angles have the same measurements.
90 + y+y = 180
y+y=90
2y = 90
y = 45
Each angle must equal 45 degrees
7x+3 = 45 degrees
Subtract 3 from each side
7x+3-3 =45-3
7x =42
Divide each side by 7
7x/7 =42/7
x =6