***HELP!!!!*****Due Today!

1)In triangle  ABC, $AB = BC = 17$ and AC = 16 Find the circumradius of triangle 

2)Angle bisectors line AX and  line BY of triangle ABC meet at point I. Find angle C in degrees, if angle AIB = 109

[asy]
pair A,B,C,X,Y,I;

A= (0,0);
B = (1,0);
C = (0.6,0.5);
X = intersectionpoint(B--C , A -- (bisectorpoint(B,A,C)));
Y = intersectionpoint(A--C, B -- scale(6)*( (bisectorpoint(C,B,A)) - B));
I = intersectionpoint(A--X, B--Y);
draw(X--A--C--B--Y);
draw(A--B);
label("$A$",A,SW);
label("$B$",B,SE);
label("$C$",C,N);
label("$I$",I,S);
label("$X$",X,NE);
label("$Y$",Y,NW);
[/asy]

3)A certain square and a certain equilateral triangle have the same perimeter. The square and triangle are inscribed in circles, as shown below. If A is the area of the circle containing the square, and B is the area of the circle containing the triangle, then find A/B

4) $\overline{BY}$ and $\overline{CZ}$ are angle bisectors of triangle $ABC$ that meet at  I, with $CY = 4$, $AY = 6$, and $AB = 8$. Find 

$BZ$

.