Mathematics

Problem

\triangle ABC

and

\triangle DEF

AB = 3x - 4\ \text{cm}

DE = 11\ \text{cm}

AC = 2x + 1\ \text{cm}

DF = 2x + 1\ \text{cm}

and

\angle A = \angle D = 60^\circ

. For what value of

x

are the two triangles congruent by the SAS criterion? a)

x = 6

x = \dfrac{7}{3}

x = 5

x = \dfrac{14}{5}