Finding the Hypotenuse and
the Side Opposite q of a Right Triangle
This week, we are going to
teach you how to find the side opposite q on a right triangle.
Teaser: Raspune's ship
contains a store of plasma fuel behind a triangular panel. The panel is shaped like a right triangle
with q equal to 75 degrees and the side adjacent q equal to 2.25 meters. How long is the hypotenuse? The side opposite q?

hypotenuse = side adjacent q / cos q
side
opposite q = side adjacent q (tan q)
Example 1: Given a right triangle with y = 5
cm and q = 50o find the
hypotenuse
and x.
hypotenuse = side adjacent q / cos q
Formula
hypotenuse = 5 cm/cos 50o
q = 500 and y = 5 cm
hypotenuse = 5 cm/ .6427
cos 50o
= .6427
hypotenuse = 7.8 cm
5 divided by .6427
side opposite q = side adjacent q (tan q)
Formula
side opposite q = 5 cm (tan 50o)
q = 50o
and side adjacent q = 5cm
side opposite q = 5 cm (1.1918)
Tan 50o
= 1.1918
side opposite q = 6.0 cm
5 times 1.1918
Example 2:
Given a right triangle with y = 9.1 in and q = 30o find the
hypotenuse and x.

hypotenuse = side adjacent q / cos q
Formula
hypotenuse = 9.1 in/cos 30o
side adjacent q = 300 and x = 9.1
hypotenuse = 9.1 in/ .8660
cos 30o
= .8660
hypotenuse = 10.5 in
9.1 divided by
.8660
side opposite q = side adjacent q (tan q)
Formula
side opposite q = 9.1 in (tan 30o)
q = 30o
and side adjacent q = 9.1
side opposite q = 9.1 in
(.5774)
Tan 30o
= .5774
side opposite q = 5.3 in
5 times .5774
Problems:
1) Given a right
triangle with y = 12 cm and q = 60o find the
hypotenuse and side opposite q.
2) Given a right
triangle with y = 3.5 in and q = 83o find the
hypotenuse and side opposite q.
3) Given a right triangle with y = 60 mm and q = 25o find the hypotenuse and side
opposite q.
4) Given a right triangle with y = 5.7 in and q = 45o find the hypotenuse and
side opposite q.
*Note: The triangles
shown on this and previous weeks may not coincide with actual proportions. We apologize for any inconvenience we may
have caused.