Inverse SOHCAHTOA Way vs Interior Angle Sum
What is the degree measure of LNM?
Alternately, you could use the inverse of one of the SOHCAHTOA functions, in this case the inverse of sine (sin-1)! To find, an angle of a right triangle all that we need to know is the length of two sides! Then use the same SOHCAHTOA ratios --just in a different fashion See the example below.
YouTube Vid: How to Calculate Inverse SOHCAHTOA
A good video on how to use your a TI-Graphing Calculator to calculate the inverse sine,cosine or tangent.
Compare sine with inverse sine.General Difference: sine is the ratio of two actual sides of a right triangle (the opposite & hypotenuse) sin(B) = AC/AB
Inverse or sin-1 is an operation that uses the same two sides of a right triangle as sine does (opposite over hypotenuse) in order to find the measure of the angle (in this case b) sin-1(AC/AB) = measure of angle B
Key difference: Although both sine and inverse sine involve the opposite side and hypotenuse of a right triangle, the result of these two operations are very, very different. One operation (sine) finds the ratio of these two sides; the other operation, sine inverse, actually calculates the measure of the angle (B in the example above) using the opposite side and the hypotenuse.
Use inverse sine, cosine or tangent to calculate the measure of the shaded angle on the left.
Since you know all 3 sides, you could use any of the following:= sin-1(7/25) = 16.3°
= cos-1(6/15) = 16.3°
= tan-1(7/24) = 16.3°
Since you know all 3 sides, you could use any of the following:= sin-1(8/10) = 53.13°
= cos-1(6/10) = 53.13°
= tan-1(8/6) = 53.13°