17. A 3 by 2 rectangle is split into four congruent right-angled triangles, as shown in the left-hand diagram.
Those four triangles are rearranged to form a rhombus, as shown in the right-hand diagram.
What is the ratio of the perimeter of the rectangle to the perimeter of the rhombus?

A $3: 2$
B $2: 1$
C $1: 1$
D $1: 2$
E $2: 3$
17. C First note that the perimeter of the rectangle is $2(2+3)=10$.
The diagram shows one of the four congruent triangles into which the rectangle is divided.
By Pythagoras' Theorem, $l^{2}=2^{2}+1.5^{2}=4+2.25=6.25$.
Therefore $l=\sqrt{6.25}=2.5$. So the perimeter of the rhombus is $4 \times 2.5=10$.
Hence the ratio of the two perimeters is $10: 10=1: 1$.