(i) From the figure we know that △EDC is an equilateral triangleso we get ∠EDC=∠ECD=60oWe know that ABCD is a squareso we get ∠CDA=∠DCB=90oconsider △EDAwe get∠EDA=60o+90oso we get∠EDA=150o....(1)Consider △ECBwe get∠ECB=∠ECD+∠DCBby substituting the values in the above equation∠ECB=60o+90owe get∠ECB=150oso we get ∠EDA=∠ECB....(ii)consider △EDA and △ECBfrom the figure we know that ED and EC are the sides of an equilateral triangleso we getED=ECwe also know that the sides of the square are equalDA=CBby SAS congruence criterion△EDA≅△ECBAE=BE(ii) consider △EDAwe know thatED=DAfrom the figure we know that the base angles are equal∠DEA=∠DAEbased on equation (i) we get ∠EDA=150oby angle sum property∠EDA+∠DAE+∠DEA=180oby substituting the values we get150o+∠DAE+∠DEA=180owe know that ∠DEA=∠DAEso we get150o+∠DAE+∠DAE=180o2∠DEA=180o−150o∠DAE=15o