New Scientist - 15.02.2020

52 | New Scientist | 15 February 2020

The back pages Puzzles

Quick crossword #51 Set by Richard Smyth Quick quiz #38 Puzzle set by Zoe Mensch

#46 Pi-thagoras

Pythagoras’s

theorem says

that for any

right-angled

triangle, the

square of the

hypotenuse (the

longest side of

the triangle) is equal to the sum of

the squares of the other two sides.

There are some right-angled triangles

whose sides are all whole number lengths.

The simplest and best known is the

“3-4-5” triangle (3^2 + 4^2 = 5^2 ).

I have drawn a circle that fits precisely

inside a 3-4-5 triangle. What is the area

of the circle? Have a guess. And then

see if you can prove that you are right.

Answer next week

#45 Beetles on a clothes line

Solution

The last two beetles to drop off the line, both

after 2 minutes, are beetle B at the left-hand

end and beetle C at the right-hand end.

When two beetles meet, they reverse

direction. But blur your eyes and you may

see that this is equivalent to the two beetles

walking past each other on parallel paths.

So, a beetle that starts at one end will walk

2 metres (taking 2 minutes) before dropping

off the opposite end. Four beetles are

pointing to the right at the start, so we will

see four of them drop off the right-hand end,

and since beetles can’t actually go past each

other, the beetle that starts four places

from the right (beetle C) must be the last

one that drops off the right-hand end.

By the same reasoning, two beetles fall off to

the left, the second of these being beetle B.

1 Based on their different

neurobiology, lust, attraction

and attachment are the

three main subcategories

of what?

2 Which of the three is

thought to be principally

mediated by the hormones

dopamine, norepinephrine

and serotonin?

3 Also known as the “cuddle

hormone”, which peptide

hormone plays a major part

in social and reproductive

attachment in many

mammal species?

4 The medication sildenafil,

sold under the brand name

Viagra among others, was

originally developed as a

treatment for what?

5 During the mating season,

what accounts for up to

63 per cent of a female

praying mantis’s diet,

according to a 2016 study?

Answers below

Cryptic

Crossword #24

Answers

ACROSS 1/4/16 Twenty

twenty vision, 9 Tornado,

10 Newts, 11 Nasal,

12 Precede, 13 Regrettable,

18 Integer, 20/23 Helen

Sharman, 22 Irate,

24 Natant, 25 Stoner

DOWN 1 Tetany, 2 Earns,

3 Trailer, 5 Wince, 7 Yes-men,

8 Computerise, 14 Extract,

15 At heart, 17 Inaner,

19/6 Green New Deal,

21 Lumen

Quick quiz #38

Answers

Love 1

Sexual attraction 2

Oxytocin 3

Heart-related 4

chest pain, or angina

Male praying mantises 5





 

 

    

  

    

 



ACROSS

1 Typically, having only

length and width (3-11)

10 Item seized by Wittgenstein

in a 1946 debate (5)

11 Broadcast; schedule;

curriculum (9)

12 Absence of an

organ or tissue (7)

13 The ___ Cuckoos, 1957

John Wyndham novel (7)

14 Electronic

correspondence (5)

16 Disconnector switches (9)

19 Piscivorous raptor (4-5)

20 Acidic compound

used as a stain (5)

22 Unwanted parts of

a mineral deposit (7)

25 ___ at the nest, term in

ecology for juveniles that

assist in brood-raising (7)

27 Messier 31 (9)

28 Scorched; overheated (5)

29 Theory of lithospheric

movement (5,9)

Answers and the next cryptic crossword next week.

DOWN

2 Publisher of classified

data, founded by Julian

Assange (9)

3 French satellite system;

large main-belt asteroid (5)

4 Cartography (9)

5 Rice paddy herb,

Limnophila aromatica (3,2)

6 Expose to radiation (9)

7 Maths game devised

by Piet Hein (5)

8 Invertebrate

phlebotomists (7)

9 Morphine or

codeine, say (6)

15 Fructose (9)

17 Form of major surgery (4,5)

18 Relating to childbirth (9)

19 Light used in

misty weather (7)

21 Space station? (4-2)

23 Ephenidine (5)

24 Central part of a

root or stem (5)

26 ___ a Chip, journal

of miniaturisation (3,2)

Our crosswords are

now solvable online

Available at

newscientist.com/crosswords

3 5

4

ABCDE F