Question on triangometry which one we measure ?

[r-soy]

see the pic

[PLAIN]http://store2.up-00.com/Oct10/opW54159.jpg

 

[pongo38]

She measures 100 m long the bank, and the angle of 35 degrees. Then concludes the distance A using trigonometry. Does that answer your question? If B were required, that could also be done with trigonometry, but it wouldn't be the shortest distance, which most people would be interested in.

 

[Mentallic]

This is really just common sense... If asked to measure the width of say, a pencil, you don't start from the left bottom corner of the pencil and measure up to the top right corner, you measure straight across.

 

[Mark44]

The caption on the picture says "To measure The wide of river we measure A or B" Your picture doesn't show it, but the width of the river seems to be A, and we walk 100 m along the river bank. Unless we are able to walk across the river, we don't measure its width (A) or the length of the diagonal (B). These are calculated values, not measured values.

 

[r-soy]

thanks