Euclidean geometry equal (SAS), or two angles and a side equal (ASA) (Book I, propositions 4, 8, and 26). Triangles with three equal angles (AAA) are similar, but not necessarily congruent. Also, triangles with two equal sides and an adjacent angle are not necessarily equal or congruent. The sum of the angles of a triangle is equal to a straight angle (180 degrees). This causes an equilateral triangle to have three interior angles of 60 degrees. Also, it causes every triangle to have at least two acute angles and up to one obtuse or right angle. The celebrated Pythagorean theorem (book I,
Clock angle problem through 360° in 60 minutes or 6° per minute. where: where: The time is 5:24. The angle in degrees of the hour hand is: The angle in degrees of the minute hand is: The angle between the hands can be found using the following formula: where If the angle is greater than 180 degrees then subtract it from 360 degrees. The time is 2:20. The time is 10:16. The hour and minute hands are superimposed only when their angle is the same. 10:54., and 12:00. Clock angle problem Clock angle problems are a type of mathematical problem which involve finding