In figure, ABCD is a square and ∠DEC is an equilateral triangle. Prove that
(i) ∆ADE ≅ ∆BCE
(ii) AE = BE
(iii) ∠DAE = 15°
Given: In figure, ∠x = ∠y and PQ = PR
To Prove: PE = RS
Construction: Join PR
Proof: In ∆PQR,
∵ PQ = QR | Given
∴ ∠QRP = ∠QPR
| Angles opposite to equal sides of a triangle are equal
⇒ ∠ERP = ∠SPR ...(1)
In ∆PER and ∆RSP,
∠ERP = ∠SPR From (1)
∠REP = ∠PSR | Given
PR = RP | Common
∴ ∆PER ≅ ∆RSP
| AAS congruence rule
∴ PE = RS | CPCT