Yeah there all right but I have a little hinch for the last and first one
Answer: 314 mm
Step-by-step explanation:
Area of a circle is π*r^2
r is radius and π is 3.14
here the radius is 10
3.14 * 10^2 = 3.14 * 100 = 314
-3(c-10) + -4= 2
-3c+ 30+ -4= 2
-3c + 26= 2
-3c= -24
C= 8