Solve the proportion 12/x=x/4
Please give step by step instructions!

The figure above shows the lengths of thesides of a rectangle in cm. find the valuesof x and y and then the area of the rectangle.sides: top= 3x - yleft= 3y + 4bottom= 2x + yright= 2x - 3 use both methods, elimination and substitution, if possible.

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.