document.write( "Question 896311: ABDE is a square section and BDC is an equilateral triangle with C outside the square. Compute the value of angle ACE. \n" ); document.write( "
Algebra.Com's Answer #543391 by Theo(13342)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "see the following diagram.
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\n" ); document.write( "\n" ); document.write( "your equilateral triangle is BCD.
\n" ); document.write( "since it's an equilateral triangle, all angles are equal to 60 degrees.
\n" ); document.write( "you draw a line from A to C and from E to C.
\n" ); document.write( "this forms 2 isosceles triangles of ABC and EDC.
\n" ); document.write( "the congruent legs of triangle ABC are:
\n" ); document.write( "AB and BC
\n" ); document.write( "the congruent legs of triangle EDC are:
\n" ); document.write( "ED and DC
\n" ); document.write( "the angles opposite these congruent legs are equal.
\n" ); document.write( "the angles that are equal for triangle ABC are:
\n" ); document.write( "angle BAC and angle BCA
\n" ); document.write( "the angles that are equal for triangle EDC are:
\n" ); document.write( "angle DEC and angle DCE
\n" ); document.write( "angle ABC is composed of angle ABD which is 90 degrees and angle CBD which is 60 degrees. angle ABC is therefore equal to 150 degrees because 90 + 60 = 150.
\n" ); document.write( "since the sum of the angles of a triangle is equal to 180 degrees, this means that angles BAC and BCA must be equal to 30 degrees in total because angle ABC is equal to 150 degrees.
\n" ); document.write( "since those angles are equal, then each of them must be equal to 15 degrees.
\n" ); document.write( "similarly angles DEC and DCE must each be equal to 15 degrees also.
\n" ); document.write( "the angle in question is angle ACE which is the third part of angle C which is equal to 60 degrees.
\n" ); document.write( "the first part is angle BCA which is equal to 15 degrees.
\n" ); document.write( "the second part is angle DCE which is equal to 15 degrees.
\n" ); document.write( "the third part is angle ACE which has to be equal to 30 degrees since 60 - 15 - 15 = 30.\r
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\n" ); document.write( "\n" ); document.write( "that's your answer.
\n" ); document.write( "angle ACE is equal to 30 degrees.
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