Mathematics × Programming Competition #7

^{Designed by @nicolemoker}

21/9/2017 UTC 04:00 - 28/9/2017 UTC 04:00

*For Chinese version please scroll to the bottom. 中文版請見文末。*

## Question

A point is chosen randomly in a square. 4 lines are drawn to connect this point with the 4 vertices of this square, such that 4 triangles are formed. Find the probability that all interior angles of the 4 triangles are less than 120°. Give your answer correct to the nearest 3 decimal places.

Answer submission

Please submit your answer through this link.

Rules

- This competition will last for 7 days. After that, no more submission will be accepted.
- Participants who submit the answer as a comment below this post will be
**disqualified**. - Participants can submit an unlimited number of solutions, however only the latest answer will be considered.
- You have to upvote this post in order to be eligible for the competition.

Prizes

- The three fastest contestants would win the first prize, second prize and third prize respectively.
- Other contestants who gave the correct answer would enter a lucky draw. 5 winners will be drawn.
- Those who
**resteemed**this post will have 400% higher chance to win in the lucky draw. - @kenchung reserves all the rights to disqualify any suspected cheating players and to decide the distribution of prizes among the winner(s).

Name of prize | Max no. of prizes | SBD | SP (sponsored by @steemstem ! ) |
---|---|---|---|

First prize | 1 | SBD payout of this post / n | 7.5 |

Second prize | 1 | SBD payout of this post / n | 5 |

Third prize | 1 | SBD payout of this post / n | 2.5 |

Consolation prize | 5 | SBD payout of this post / n | 0 |

where *n* is the total number of winners in this competition. *n* = min (number of participants getting the correct answer, 8).

The steemSTEM project (@steemstem) is a community-supported project aiming to increase the quality and the visibility of STEM (STEM is the acronym for Science, Technology, Engineering and Mathematics) articles on Steemit. Please support steemSTEM by following @steemstem and joining the chat channel. You can also consider joining a private curation trail to further support steemSTEM by asking about it in the chat channel. In order to further promote the use of the chat channel, I will stop announcing the time of next competition via a post. Instead I will announce the time in advance in the chat channel!

數學 × 程式編寫比賽 (第七回)

^{Designed by @nicolemoker}

21/9/2017 UTC 04:00 - 28/9/2017 UTC 04:00

## 問題

在一個正方形內隨機選取一點，並將此點與四個頂點連上直線，從而將正方形分割為四個三角形。求四個三角形之中所有內角均不超過 120° 的概率，答案準確至小數點後 3 位。

答案提交

請經此連結提交答案。

規則

- 此比賽為時7天，其後將不會再接受新答案。
- 嚴禁在回覆公開答案，否則將被取消資格。
- 參加者可以重覆提交答案，但比賽終結時只會考慮最後提交的答案。
- 你必須upvote此帖方能參加比賽。

獎品

- 最快給出正確答案的三名參賽者將分別獲得一等獎、二等獎和三等獎。
- 其他給出正確答案的參賽者將可參與抽獎。5名參賽者將被選出。
- Resteem此帖文者將有額外400％的得獎機會。
- 本人保留一切最終權利，包括但不限於取消任何疑似作弊者的資格並決定獲獎者的獎勵分配。

獎項 | 獎項數目 | SBD | SP (由 @steemstem 贊助！) |
---|---|---|---|

一等獎 | 1 | 此帖文的 SBD 金額 / n | 7.5 |

二等獎 | 1 | 此帖文的 SBD 金額 / n | 5 |

三等獎 | 1 | 此帖文的 SBD 金額 / n | 2.5 |

安慰獎 | 5 | 此帖文的 SBD 金額 / n | 0 |

其中 *n* 是本比賽中得獎者的總數。*n* = min (答對人數, 8)。

steemSTEM（@steemstem）是一個由steemit社群支持的項目，旨在宣傳STEM（STEM是科學，技術，工程和數學的首字母縮略詞）。 請追蹤 @steemSTEM 以及加入聊天頻道來支持steemSTEM。你還可以透過加入自動點讚系統來在為了進一步支持steemSTEM，詳情請在聊天頻道內向負責人士查詢。為了推廣聊天頻道的使用，我將不再透過發文來宣布下一場比賽的時間，我會在聊天頻道中提前公佈比賽時間。

justyy (70)· 7 months agoI hope i win this time :P (voted and resteeeeeeeeeeeeeeeeeeeem)

kenchung (63)· 7 months agosure best of luck! :p

armandocat (63)· 7 months agoJust to be sure, if my solution would be 0.55%, I should submit 0.006.. correct?

(that is not my solution btw 😼)

kenchung (63)· 7 months agoyes that's right :)

bitgeek (61)· 7 months agoCongratulations @kenchung, this post is the ninth most rewarded post (based on pending payouts) in the last 12 hours written by a Superuser account holder (accounts that hold between 1 and 10 Mega Vests). The total number of posts by Superuser account holders during this period was 703 and the total pending payments to posts in this category was $3964.13. To see the full list of highest paid posts across all accounts categories, click here.

If you do not wish to receive these messages in future, please reply stop to this comment.

leedslemon (51)· 7 months agoJust submitted the answer.. It's a very difficult one.

kenchung (63)· 7 months agoye this one is more difficult than the previous questions :) hope that you got it right!

fundurian (63)· 7 months ago读到题目就头晕了😩

kenchung (63)· 7 months ago😢😢😢

tvb (63)· 7 months ago来晚了，睡醒了已经发布好几个小时了。。。不过还是参与一下吧。争取幸运奖！

kenchung (63)· 7 months ago多謝支持啊 :)

tvb (63)· 7 months ago我也谢谢你，这个游戏 好有趣，我超级喜欢。

deepweeb (13)· 7 months agoThis is actually some astounding work! Followed

krischy (65)· 7 months ago好難呀呀🙈😂😂

kenchung (63)· 7 months ago這次是真的比較難和複雜的，不過只需用上中五的知識就可以解答的了！ ;)

tvb (63)· 7 months ago确实是好难呀，比1公斤鱼难好多。

wlcpu (41)· 7 months ago计算方法有限制吗？是否一定要编程实现？

kenchung (63)· 7 months ago解決方法不限，提交最終數字答案即可

galotta (58)· 7 months agoI have also submitted my answer, both in unit-less and percentage form in addition to the exact solution if that is ok

Hopefully without computational errors ^^

kenchung (63)· 7 months ago3 decimal places in the unit-less is fine :) anyway thanks for your participation! hope that you got the right answer :)

yuan0601 (44)· 7 months ago我就想问答案要发在哪里

kenchung (63)· 7 months ago上文有連結提供的啊

「答案提交」那一部分

noval (42)· 7 months agobusiness does not lie to results

goodboyphilip (63)· 7 months ago雖然不懂⋯也要支持！！😂

kenchung (63)· 7 months ago謝謝啦! :)

jerryhuge (12)· 7 months agochallk (39)· 7 months ago希望可以得獎!

kenchung (63)· 7 months ago謝謝參與，希望你能得獎！

shieha (70)· 7 months agoHope I got the answer :)

Awesome math puzzle!

RESTEEMED!kenchung (63)· 7 months agogreat thanks! :) hope that you can win :)

vincentyip (55)· 7 months ago這個比賽不錯，數學方式我可不懂了，不過看來編程應該不難的

支持一下!

kenchung (63)· 7 months ago謝謝支持!

cryptohazard (62)· 7 months agocool contest. I will try to tackle it when I get some free time.

kenchung (63)· 7 months agosure! :) thanks for joining!

chasmic-cosm (55)· 7 months agosubmitted... Will make a post about finding my result once the contest is over, as I'm sure it may be a somewhat different approach :)

kenchung (63)· 7 months agothanks for participation, looking forward to seeing your approach in solving this question!

speeding (52)· 7 months ago等待结果

kenchung (63)· 7 months ago這幾天比較忙，可能要遲數天才公佈，要耐心等候一下啦～

vincentyip (55)· 7 months agoi have published a post here: https://steemit.com/cn/@vincentyip/kenchung

please check it out! :)

baby07 (55)· 7 months agogreat I was not able to read this 7 days ago

kenchung (63)· 7 months agonever mind, remember to join the next competition! :)

iwant (50)· 6 months agogreat post i upvoted you & follow you please follow me & upvoted me