can you help me

Question

three forces in a plane act on a object. The forces are 7 N, 11 N, 15 N. The angle between the 7 N and 11 N is 105 degrees, between the 11 N and 15 N forces is 147 degrees, and between the 15 N and 7 N forces is 108 degrees. find the magnitude and the direction of the resultant force

Answer 1

Mark the 4 axes on an X-Y Plane with:

"Back East" or 0° for Positive X;

"Up North" or 90° for Positive Y;

"Out West" or 180° for Negative X ;

"Down South" or 270° for Negative Y.

For the Magnitudes & Directions given, write and sum 

the two columns below (where i and j are unit vectors

in the X & Y directions):

--------------7cos 0°i---------+-----------7sin 0°j

-------------11cos(0+105)°i ----+-----11sin (0+105)°j

-------------15 cos(105+147)°i --+--15sin (105+147)°j

********************************************

(-0.4822644118)i----------+-------------(-3.640663655)j

Take the magnitude of the vector sought as 

[(-0.4822644118)² + (-3.640663655)²]^0.5

equal to 3.672466584 Newtons.

Direction of the vector sought is given by

arctan[(-3.640663655) ÷ (-0.4822644118)] + 180°

equal to 262.4541847°.