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The diagram shows an aggregate demand (C+I) function, a consumption function (C), a planned investment function (I) and a 45 degree line.

The vertical axis is labelled as ‘Aggregate Demand (C+I)’ and is marked from 0 to 640, at intervals of 40. The horizontal axis is labelled as ‘Income (Y)’ and is marked from 0 to 650, at intervals of 50.

The 45 degree line slopes up from the origin.

The planned investment line (I) is horizontal, drawn across from the point 80 point on the vertical aggregate demand (C+I) axis.

The consumption function (C) slopes upward more shallowly than the 45 degree line, from the point 100 on the vertical axis.

The Aggregate Demand function (C+I) is in shown in blue and lies above and is parallel to the consumption function (C). It slopes upward from the 180 point on the vertical axis. The vertical gap between the C+I and the C function is equal to the value of planned investment (I).

The Aggregate Demand (C+I) function intersects the 45 degree line at an income level of 600. At this point, Aggregate Demand also equals 600.

 4.4 And so to equilibrium