# pre-cal

posted by
**devin** on
.

to find the distance AB across a river, a distance BC= 309m is laid off on one side of the river. It is found that B= 105.4 degrees and C= 12.2 degrees. Find AB

To find the distance AB across a river, a distance BC= 309m is laid off on one side of the river. It is found that /_B= 105.4 degrees and /_C = 12.2 degrees. Find AB

If angle B is 105.4º, distance AB is not normal to the banks of the river, assuming the banks are parallel.

With the given information, distance AB may be found using the Law oof Sines. WIth /_A being 180 - 105.4 - 12.2 = 62.4º, AB/sin(12.2) = 308/sin(62.4).

Solve for AB.