An angle of 180 ° will represent a straight line.
If we look at the figure < A consists of four angle .The four angles are <BAC,<CAD ,<DAE and <BAE. All these angles are less than 180°
Other angles which are less than 180 ° in the given figure are <ABE,<ACB,<ACD,<ADC,<ADE and <AED that is 6 in all.
The total angles which are less than 180° in the given figure is 4+6=10 in all.