document.write( "Question 1199846: ABCD and DEFG are congruent squares. Find the measurement of angle ACF
\n" ); document.write( "image: https://imgur.com/a/5fK4nvs \n" ); document.write( "
Algebra.Com's Answer #833835 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Since DC=DE and ∠CDE = 60o, △CDE is equilateral.\r\n" );
document.write( "Therefore all the line segments except CF and AC are equal in length.\r\n" );
document.write( "\r\n" );
document.write( "∠CED = 60o because △CDE is equilateral.\r\n" );
document.write( "∠DEF = 90o because it is an internal angle of square DEFG\r\n" );
document.write( "∠CED + ∠DEF = 60o + 90o = 150o\r\n" );
document.write( "△CEF is isosceles because CE = EF.\r\n" );
document.write( "The base angles of △CEF are equal in measure, and we can find them\r\n" );
document.write( "by subtracting 180o-150o = 30o, and\r\n" );
document.write( "then taking half and getting 15o.\r\n" );
document.write( "So base ∠ECF = 15o,\r\n" );
document.write( "∠DCE = 60o because △CDE is equilateral.\r\n" );
document.write( "∠DCF = ∠DCE-∠ECF = 60o-15o = 45o\r\n" );
document.write( "∠ACD = 45o because △ADC is an isosceles right triangle\r\n" );
document.write( "∠ACF = ∠DCF + ∠ACD = 45o + 45o = 90o\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\n" ); document.write( "
\n" );