Answer:
The true statements are the first three.
Explanation:
First statement
According to pythagorus's theorem, the square of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the other two sides. This is what the first statement says, so it is true.
Second statement
The 4 blocks north and 8 blocks east Mary travels can be drawn as shown below. If we construct a direct line from the start to the end of her journey, we now have a right-angled triangle, with this direct line as the hypotenuse. So we can use pythagorus's theorem, as explained above, to find the length of this line.
The sum of the squares of the other two sides is: 4²+8²=16+64=80
So the hypotenuse, or direct line, is the square root of this: √80=√(4²)(5)=4√5.
This distance divided by √5 is in fact 4, so the second statement is true.
Third statement
The distance Mary would travel in a direct line is 4√5 which is equal to roughly 8.944, which is just under 9blocks. So the third statement is also true.
Fourth statement
We have figured out that the first three statements are true, so the claim none of them are true is false.
Hope this helps! Let me know if you have any questions :)