Question

prove that sum of two acute angle is less than 180

Answer 1

the sum of two acute angles will surely be less than 180 as acute angles are less than 90 degrees  and they cannot be more than 89 degrees. 90+90 will be 180 and 89+89 will be 178 and than is less than 180

Answer 2

180° is the total sum of all the angles in a right triangle

angle a + angle b + 90° = 180°

angle a + angle b + 90° - 90° = 180° - 90°

angle a + angle b = 90°