Question 1199846
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<pre>
(a)  Triangle CDE is equilateral triangle 
     (since it is isosceles CD = ED and the angle between 
      these congruent sides is 60°).

      Therefore, all its interior angles are 60° each.



(b)  angle ACE is 45° + 60° = 105°.

     angle CEF is 60° + 90° = 150°.



(c)  Triangle CEF is isosceles, since  CE = EF.

     Therefore, angle FCE = {{{(180-150)/2}}} = {{{30/2}}} = 15°.



(d)  < ACF = < ACE - < FCE = 105° - 15° = 90°.



<U>ANSWER</U>.  Angle ACF is 90° (right angle).
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