Digit is one an my
s digit.
reds digit is
number
5 and 7.
aligit is the
of vertices
I'm an even number
between 100 and
200.
The sum of my digits
is 14.
My tens digit is two
less than nine.
What am I?

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?