If a and b are the lengths of the legs of a right triangle and c is the length of the hypotenuse, then the sum of the squares of the lengths of the legs is equal to the square of the length of the hypotenuse.

Key Takeaways

1. The Pythagorean Theorem, a2+b2=c2, a 2 + b 2 = c 2 , is used to find the length of any side of a right triangle.
2. In a right triangle, one of the angles has a value of 90 degrees.
3. The longest side of a right triangle is called the hypotenuse, and it is the side that is opposite the 90 degree angle.

“SAS” is when we know two sides and the angle between them. use The Law of Cosines to calculate the unknown side, then use The Law of Sines to find the smaller of the other two angles, and then use the three angles add to 180° to find the last angle.

Key Points

1. The Pythagorean Theorem, a2+b2=c2, a 2 + b 2 = c 2 , is used to find the length of any side of a right triangle.
2. In a right triangle, one of the angles has a value of 90 degrees.
3. The longest side of a right triangle is called the hypotenuse, and it is the side that is opposite the 90 degree angle.

Finding an Angle in a Right Angled Triangle

1. Step 1: find the names of the two sides we know.
2. Step 2: now use the first letters of those two sides (Opposite and Hypotenuse) and the phrase “SOHCAHTOA” to find which one of Sine, Cosine or Tangent to use:
3. Step 3: Put our values into the Sine equation:
4. Step 4: Now solve that equation!

A 30-degree angle is an acute angle because it is less than 90 degrees.

Place the compass point at B, and using the same radius, strike another arc within the rays. Label as C the point of intersection of the two arcs. Draw a straight line from the angle’s vertex to point C. That line bisects the 60° angle, forming two 30° angles.

How to Find 180-Degree Angle?

1. Draw a straight line which will be the arm of angle.
2. Put a dot at one end of the line.
3. Now place the center of the protractor above the dot or vertex and match the baseline of the protractor along with the arm of the angle.
4. Mark the angle 180 degrees with a dot.

acute angle-an angle between 0 and 90 degrees. right angle-an 90 degree angle. obtuse angle-an angle between 90 and 180 degrees. straight angle-a 180 degree angle.