Answer:
Part 9) 
Part 10) 
Part 11) 
Part 12)





Part 13) The measure of each side is 56 units
Part 14)




Part 15)




Step-by-step explanation:
Part 9) we know that
An isosceles triangle has two equal sides and two equal interior angles
The triangle of the problem is an isosceles triangle
Because has two equal sides and two equal angles
Remember
The sum of the interior angles in any triangle must be equal to 180 degrees
so

solve for x

Part 10) we know that
step 1
Solve for x
An isosceles triangle has two equal sides and two equal interior angles
The triangle XYZ of the problem is an isosceles triangle
Because has two equal sides
so

substitute the given values

solve for x

Find the measure of angle X

substitute the value of x

so

step 2
Find the measure of angle Y
Remember
The sum of the interior angles in any triangle must be equal to 180 degrees
so


Part 11) we know that
we know that
An equilateral triangle has three equal sides and three equal interior angles. The measure of each interior angle is 60 degrees
In this problem we have an equilateral triangle
so

solve for x

Part 12)
step 1
Find the measure of angle 1
we know that
An equilateral triangle has three equal sides and three equal interior angles. The measure of each interior angle is 60 degrees
In this problem the triangle WXY is an equilateral triangle
therefore

step 2
Find the measure of angle 3
we know that
Triangle WZY is an isosceles triangle
so

Remember that
The sum of the interior angles in any triangle must be equal to 180 degrees
so



so

step 3
Find the measure of angle 2
we know that
The measure of each interior angle of an equilateral triangle is equal to 60 degrees
so

substitute the given value



step 4
Find the measure of angle 4
we know that
The measure of each interior angle of an equilateral triangle is equal to 60 degrees
so

substitute the given value



Part 13) we know that
we know that
An equilateral triangle has three equal sides and three equal interior angles. The measure of each interior angle is 60 degrees
so
AB=BC=AC
solve the equation
AB=BC
substitute the given values

Find the measure of side AB

substitute the value of x

Verify BC and AC
----> is correct
----> is correct
Part 14) we know that
An isosceles triangle has two equal sides and two equal angles
In this problem Triangle HIJ is an isosceles triangle
because
Angle I is equal to Angle J
so
HI=HJ
substitute the given values

solve for x

Find the measure of each side



Part 15) we know that
Triangle ACD is an isosceles triangle
because
has two equal sides
AC=AD
so

substitute the given values

solve for x

Find the measure of angle C

Find the measure of angle D

Find the measure of angle A
we have that

substitute


