ABC is a triangle. BAD is 40 degrees, DAC is 20 degrees, ABE is 60 degrees and DBE is 10 degrees. What is angle CDE (angle x)?

enter image source here

1 Answer
CW
Apr 28, 2018

#x=30^@#

Explanation:

enter image source here
#angleADB=180-angleABD-angleBAD=180-70-40=70^@#
#=> DeltaABD# is isosceles, #=> color(red)(AB=AD)#,
#angleAEB=180-angleABE-angleBAE=180-60-60=60^@#
#=> DeltaABE# is equilateral,
#=> AE=AB, => color(red)(AE=AD)#,
#=> DeltaADE# is isosceles,
#=> angleADE=angleAED=(180-20)/2=80^@#
#=> angleCDE=x=180-angleADB-angleADE=180-70-80=30^@#

Related questions
Impact of this question
1996 views around the world
You can reuse this answer
Creative Commons License