1978 AHSME Problems/Problem 12

Problem

In $\triangle ADE$, $\measuredangle ADE=140^\circ$, points $B$ and $C$ lie on sides $AD$ and $AE$, respectively, and points $A,~B,~C,~D,~E$ are distinct.* If lengths $AB,~BC,~CD$, and $DE$ are all equal, then the measure of $\measuredangle EAD$ is

  • The specification that points $A,B,C,D,E$ be distinct was not included in the original statement of the problem.

If $B=D$, then $C=E$ and $\measuredangle EAD=20^\circ$.

$\textbf{(A) }5^\circ\qquad \textbf{(B) }6^\circ\qquad \textbf{(C) }7.5^\circ\qquad \textbf{(D) }8^\circ\qquad \textbf{(E) }10^\circ$

See Also

1978 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 11
Followed by
Problem 13
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