Come on think about this one....
Perimeter means (in layman terms) around the outside (eg. a perimeter fence). What is the length around the triangle with sides equal to 10 ft, 15 ft, and 17. Not surprisingly, you just add the lengths up (ie. P= S1+S2+S3 or Perimeter = Side 1 + Side 2 + Side 3
The equation C=2Π r is saying that the circumference of a circle equals 2 x pi x radius
C = 2 x 10.5 x 3.14 (give answer to nearest whole number)
I'll leave you to do the basic calculations.....
+4 
