Question

Use Circle O to for exercises 6-8 (I need the answers for 7 & 8)

Answer 1

See  the attached picture with letters to better understand the problem

Part 8) 
we know that
The angle bisectors of a triangle intersect in a point (incenter) that is equidistant from the three sides of the triangle
so
OF=OD=OE-----> are the radii of the inscribed circle

the triangle ODB and the triangle OBE are congruent
so

applying the Pythagoras Theorem
OB²=OD²+DB²------> solve for OD
OD²=OB²-DB²------> (√28)²-5²-----> OD²=28-25-----> OD=√3 units

radius is equal to OD
therefore

the answer part 8) is
radius is √3 units

Part 9) What is the value of x? 

we know that
in the quadrilateral FOEC the sum of the internal angles must be equal to 360 degrees
so
360=90+90+60+x
x=360-240
x=120°

the answer Part 8)  is
x=120°