if angle S and angle T are complimentry and angle T and angle U are supplementry, then angle U is an ____________ angle. What kind of angle?  

Expert Answers
hala718 eNotes educator| Certified Educator

==> S and T are complimentary angles.

==> A+T = 90 degrees............(1)

==> T and U are supplementary angles.

==> U + T = 180 degrees............(2)

We will subtract (1) from (2).

==> U-A = 90 degrees.

==> U = 90+A

Then we conclude that U is an angle greater than 90 but less than 180 since A can not be greater than 90 because it is a complement angle for T.

Since U is greater that 90 degrees and less than 180, then U is an OBTUSE angle.

yeauh | Student

if s+t=90 degrees

t=45 degrees

t+u=180

so, 45+u=180

180-45=135

135 degrees= an obtuse angle!!

yay!!