Mathematics 32 Online
OpenStudy (anonymous):

Find the area of triangle PQR if P is (3,18),Q(-5,7) and R is (13,1). Please Explain how you got the answer

OpenStudy (anonymous):

Two Options: There is a formula from coordinate geometry, but it is difficult to remember (I can show you if you want), or we would need to find the side lengths using distance formula, then use the law of cosines to find an angle, then we can use a simple formula from trigonometry to find the area.

OpenStudy (anonymous):

okk

OpenStudy (anonymous):

OpenStudy (anonymous):

The formula is quicker than the second method. $Area=\frac{1}{2}|P _{x}(Q _{y}-R _{y})+Q _{x}(R _{y}-P_{y})R_{x}(P_{y}-Q_{y})|$where Px is the x-coordinate of point P, Qy=the y-coordinate of point Q, etc. For your triangle,$Area=\frac{1}{2}|3(7-1)+(-5)(1-18)+13(18-7)|=123$

Latest Questions
brianagatica14: Any artist on here?
3 hours ago 7 Replies 2 Medals
Uniful3: Art dump..
5 hours ago 8 Replies 1 Medal
mimix: hii i miss everyone
1 day ago 4 Replies 0 Medals
hellokitty265: Art
23 hours ago 13 Replies 1 Medal
TarTar: Any Songwriters here???
10 hours ago 26 Replies 2 Medals