Answer
a) 4$\sqrt 5$ $\approx$ 8.94in
b) 48cm
Work Step by Step
a)
area of square + area of triangle (that is half the size of square)
$y^{2}$ +$\frac{1}{2}$$y^{2}$ =120
$\frac{3}{2}$$y^{2}$=120
3$y^{2}$=240
$y^{2}$=80
y =4$\sqrt 5$ $\approx$ 8.94in
b)
area of the rectangle + area of the triangle
1$\times$y+$\frac{1}{2}$$y^{2}$=1200
$\frac{1}{2}$$y^{2}$ + y -1200=0
$y^{2}$ +2y -2400=0
(y+50)(y-48)=0
y is positive so the only answer is: y=48cm