Teresa solved this problem, using this
hints we gave:
The area of the equilateral triangle is
so
, so
.
We know that
and
, so
and
.
The height of the equilateral triangle is
so
.
We can use Pythagoras' Theorem to find
:
, so
.
Now we can work out
:
, so
.
From the sine rule, we have
,
so
.
Also from the sine rule,
.
By looking at the longest line across the square, we have
,
so
.
By looking at the rectangle and considering the diagonal, we see that
, so
.