Rectangle x measures 7cm by (x+1)cm. Rectangle B has dimensions of (3x+6)cm and 4cm. The area of rectangle X is half the area of rectangle Y. Calculate the lengths of the sides of the rectangles, and hence, their areas.

Sagot :

lengthxwidth=area and rectangle Y/B is twice as big as X so 

7(x+1)=1/2(4)(3x+6)
7x+7=1/2(12x+24)
x=5

Rectangle X=7(5+1)=42
Rectangle Y=4(3*5+6)=84

84 is twice as big as 42 :D