Cleave Books Puzzle Trio 5
13. 
An anagram is a word or phrase whose letters can be rearranged to make some other word or phrase.
For example: claim hat mate is an anagram of: mathematical.
Solve these, knowing each makes a single word used in mathematics.

 laces  Vi died  crust in boat 
 coster  Dina do it  cat liver 
 use ream  Sam, cheat Tim  implicit in a lot 
14. 
Starting in any cell of the grid on the right, moving up and down or across, but NOT diagonally, it is possible to make a tour which visits ALL 9 cells of the grid.
A tour may start in any one of the 9 cells.
No cell may be visited more than once (so the tour cannot cross over itself)
How many different tours are possible? 

15. 

The drawing shows 2 oblongs with ABCD resting on top of AECF.
Though the oblongs are of different sizes, corners A and C are coincident.
All edges are an exact number of centimetres in length.
What are the areas of the two smallest oblongs for which this is possible?

