Education Technology

Solution 12259: Finding the Hypotenuse and Angles of a Right Triangle on the TI-30X IIS/B Scientific Calculators.

How can I find the hypotenuse and the angles of a right triangle on the TI-30X II/B?

There is no built-in function on the TI-30X IIS/B that allows finding the hypotenuse and the angles of a right triangle.

However, this type of problem can be solved using the Pythagorean Theorem.

Example 1: Find the hypotenuse knowing that the two others sides measure 3 and 4 centimeters respectively.

Solution: The Pythagorean Theorem says that, in a right triangle, A2=B2+C2, where A is the hypotenuse, B and C the other sides. In this case the hypotenuse is side A. A is equal to the square root of the sum of the two other sides. To find A:

1) Press [2nd] [x2] to display the square root sign.
2) Input in the 3^2+4^2 in the parenthesis.
3) Press [)] to close the parenthesis.
4) Press [ENTER] to display the answer. The answer is 5.

Example 2: Find the angle opposite to a side measuring 4 centimeters when the hypotenuse measures 5 centimeters.

Solution: By definition the Sine of an angle is the opposite side divided by the hypotenuse. So, if the unknown angle is c, the sine of c is equal to 4/5 or sin (c) = 4/5. To find c, calculate the inverse sine of 4/5. Please refer to the steps provided below:

1) Make sure that DEG appears on the display (degrees mode).
2) Press [2nd] [SIN].
3) Input 4/5. The display should show sin^-1(4/5.
4) Press [)] to close the parenthesis.
5) Press [ENTER] to return the answer of 53.13 degrees.

Please see the TI-30X IIS/B guidebooks for additional information.