document.write( "Question 760836: In triangle ABC, angle A is twice as big as angle B, and angle C is 90°. Find the measures of angle A and angle B \n" ); document.write( "

Algebra.Com's Answer #462875 by Stitch(470) $\"\"$ $\"About$

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The interior angles of a triangle add up to 180.
\n" ); document.write( "So $\"A+%2B+B+%2B+C+=+180\"$
\n" ); document.write( "We are given C = 90. We can plug that into the equation.
\n" ); document.write( " $\"A+%2B+B+%2B+%2890%29+=+180\"$
\n" ); document.write( "Subtract 90 from both sides.
\n" ); document.write( " $\"A+%2B+B+=+90\"$
\n" ); document.write( "Let that be equation 1.
\n" ); document.write( "Equation 1: $\"A+%2B+B+=+90\"$
\n" ); document.write( "Equation 2: $\"A+=+2B\"$
\n" ); document.write( "Plug 2B into equation 1 for A
\n" ); document.write( " $\"2B+%2B+B+=+90\"$
\n" ); document.write( "Combine like terms
\n" ); document.write( " $\"3B+=+90\"$
\n" ); document.write( "Divide both sides by 3
\n" ); document.write( " $\"highlight%28B+=+30%29\"$
\n" ); document.write( "Now plug 30 into equation 2 for B and solve for A.
\n" ); document.write( "Equation 2: $\"A+=+2B\"$
\n" ); document.write( " $\"A+=+2%2A%2830%29\"$
\n" ); document.write( " $\"highlight_green%28A+=+60%29\"$ \n" ); document.write( "

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