A right angle measures exactly and only 90 degrees. Acute means sharp. An acute angle is a sharp angle. It will measure greater than zero degrees but less than 90 degrees. Obtuse means dull. An obtuse angle measure more than 90 degrees but less than 180 degrees. A straight angle formed by two opposite rays measures exactly 180 degrees. Angles are measured with a protractor. Most protractors have two sets of numbers so you can measure from either side. If you have an angle less than 90 degrees, use the numbers less than 90 degrees. If you have an angle more than 90 degrees, use the numbers more than 90 degrees. Check to see what two 10's is it between. The number MUST be between those numbers. Ex. between 140 and 150 is 140 something. 42 degrees 38 degrees 142 degrees 158 degrees Remember to decide if it is obtuse or acute and use the scale to match. 108 degrees 112 degrees 72 degrees 67 degrees Look to see which side the angle starts. Then look to see if it is more or less than 90 degrees. Then use those numbers. 72 degrees 68 degrees 112 degrees 108 degrees Look to see which side the angle starts. Then look to see if it is more or less than 90 degrees. Then use those numbers. 56 degrees 62 degrees 116 degrees 124 degrees Check to see what two 10's is it between. The number MUST be between those numbers. Ex. between 140 and 150 is 140 something. 42 degrees 38 degrees 142 degrees 158 degrees Look to see which side the angle starts. Then look to see if it is more or less than 90 degrees. Then use those numbers. 12 degrees 8 degrees 168 degrees 172 degrees Remember to decide if it is obtuse or acute and use the scale to match. 108 degrees 112 degrees 72 degrees 67 degrees Look to see which side the angle starts. Then look to see if it is more or less than 90 degrees. Then use those numbers. 72 degrees 68 degrees 112 degrees 108 degrees Look to see which side the angle starts. Then look to see if it is more or less than 90 degrees. Then use those numbers. 56 degrees 64 degrees 116 degrees 124 degrees Look to see which side the angle starts. Then look to see if it is more or less than 90 degrees. Then use those numbers. 56 degrees 62 degrees 116 degrees 124 degrees 42 degrees 28 degrees 142 degrees 158 degrees |