Three angles of a quadrilateral are 98 72 and 105 what is the exterior angle of the fourth angle

Alrighty, the sum of all the angles of a quadrilateral, as you might know, is 360 degrees. So since you're given all the 3 angles, you can find the 4th one by subtracting the sum of all the 3 angles from 360.

which when evaluated gives,

Now that's the interior angle not the exterior. To get the exterior we need to subtract the angle from 180 which gives:

which evaluates to .

Here's the diagram if needed :P

a. the astrolabe could determine the correct latitudinal location of the ship