= Z= We now calculate Z m (Z = length of lake in m on ground ) = B mm . A m/mm scale factor: B=_ A = We could also set this up as a proportionality: (B = length of lake in mm on ruler) B mm Y mm (Z = length of lake in mm on ground) C mm (C = # of mm in 1 km X Z mm (2 km) - - -.------ (Y = measure scale bar in mm, from 4A) 1 km (X from "1/X" in q.4C) & solve for Z, working leftward or rightward from B / Z. Z should be the same answer either way. 4E) What is the horizontal or map distance in meters from the 12250 ft contour to the 13500 ft contour (the blue circles) up the west side of Mt of the Holy Cross? Calculate & use your m / mm scale factor from 4B: m mm to 0. 1 mm from the one circle to the other mm , * scale factor --- mm m 4F) (3 pts) Elevation difference or rise = (13500 - 12250) ft = ? ft Convert to m: We will soon use E & F to calculate the slope. m PART D: INTERPOLATION BETWEEN CONTOUR LINES. Geomath 5C 5A (4 pts) What's the elevation to .01 m of point 1 (center of the X): Measure to 0.1 mm. Write #s in diagram. m 5B (4 pts) Ditto, for point 2. m N 200 An...4/5th 200 ft ........ N M 50 150 4/5th 100 20 mm 560 m ww 08 100.0 mm 150 ft elev X - elev M distance XM elev N - elev M x 1 distance NM The logic here is that, assuming a straight slope, halfway across = halfway up, 62% of the way across = 62% of the way up, etc. 550 m Show or attach work for both A & B t 2 5C) (2 pts). Why is extrapolation (point 2) less safe than interpolation (point 1)? 10