Determine the x- and y-coordinates of the centroid of the shaded area. 90 115 - 90 -160-

In orthographic projection, the lines of sight are ______ to one another a. always perpendicular b. always parallel c. neither parallel nor perpendicular

The measured photo coordinates of images a and b of two ground points A and B are x =+ 45.35 mm; ya = + 38.41 mm, x, 40.16 mm; yb 45.65 mm. Determine the ground coordinates of A and B and hence compute the horizontal length of the line AB. The elevations of points A and B are respectively 200 m and 150 m above the datum and the flying height is 1500 m above the datum. Take f = 152.4 mm.