A rectangle is divided into smaller rectangles as shown. Several of the small rectangles are labelled with their area. Find x.
+130077 Let
a = the width of the the top left rectangle
b = its height
c = the height of the bottom left rectangle
d = the width of the top rght rectangle
Then x = dc
ab = 3 ab = 3
ac = 7 db =12
b : c = 3 : 7 a : d = 3 : 12 = 1 : 4
Let b + c = 10 Let a + d = 5
Then c = 7 Then d = 4
dc = 4 * 7 = 28 = x
