document.write( "Question 1103870: Find the angle between the two vectors in -9i+ 8j, 10i- 8j \n" ); document.write( "

Algebra.Com's Answer #718602 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
Use the dot product.
\n" ); document.write( " $\"u%2Av=abs%28u%29abs%28v%29cos%28theta%29\"$
\n" ); document.write( " $\"abs%28u%29=sqrt%28%28-9%29%5E2%2B8%5E2%29=sqrt%2881%2B64%29=sqrt%28145%29\"$
\n" ); document.write( " $\"abs%28v%29=sqrt%2810%5E2%2B%28-8%29%5E2%29=sqrt%28100%2B64%29=sqrt%28164%29\"$
\n" ); document.write( " $\"u%2Av=-9%2810%29%2B%288%29%28-8%29=-90-64=-154\"$
\n" ); document.write( "So,
\n" ); document.write( " $\"cos%28theta%29=%28-154%29%2Fsqrt%28145%2A164%29\"$
\n" ); document.write( " $\"cos%28theta%29=-154%2Fsqrt%2823780%29\"$
\n" ); document.write( " $\"cos%28theta%29=-0.99865\"$
\n" ); document.write( " $\"theta=177.03\"$ \n" ); document.write( "

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