Mathematics

Problem

\triangle ABC

has sides

AB = x + 3\,\text{cm}

BC = 9\,\text{cm}

and

CA = 2y - 1\,\text{cm}

\triangle DEF

is congruent to

\triangle ABC

in the given order. In

\triangle DEF

, the corresponding sides are

DE = 12\,\text{cm}

EF = 9\,\text{cm}

and

FD = 11\,\text{cm}

. Find

x

and

y

. b. Hence, determine the perimeter of

\triangle ABC