É comum os artistas plásticos se apropriarem de entes matemáticos para produzirem, por exemplo, formas e imagens por meio de manipulações artista plástico, em uma de suas obras, pretende retratar os diversos polígonos obtidos pelas intersecções de um plano com uma pirâmide regular de base quadrada.

Segundo a classificação dos polígonos, quais deles são possíveis de serem obtidos pelo artista plástico?

Read this text about Yuri Gagarin.

Yuri was born on March 9, 1934 in Klushino, a small village 100 miles west of Moscow. His father was a cabinetmaker, carpenter, bricklayer, and farmer, and his mother was a milkmaid. Together they worked on a kolkhoz or collective farm. By Soviet social standards, his heritage was impeccable. He was the third of four children. During the war, the Nazis threw his family out of their home and took away two of his sisters. Yuri helped his parents dig a dugout where they lived untill the war was over, then the family moved to Gziatsk. 

[…] 

Yuri was subjected to extremely rigorous training: physical, mental, and psychological. He underwent long periods in a sensory deprivation chamber, experiments with weightlessness, endurance in heat chambers, and test flights under stress with every reaction monitored. […] 

"During the days of preparation for the launch, when everyone had more than his share of concerns, apprehensions, and anxieties, he alone seemed to keep calm. More than that: he was full of good spirits and beamed like the sun." 

On April 12, 1961 the first earthling escaped the gravity well of planet earth. In the spaceship Vostok 1, Senior Lieutenant Yuri Alexeyevich Gagarin orbited earth one time at an altitude of 187 3/4 miles (302 kilometers) for 108 minutes at 18,000 miles an hour. He was the first man to see that the earth was indeed round, indeed mostly water, and indeed magnificent. 

Following his return to earth, Yuri's triumphant walk through Red Square in front of a crowd of hundreds of thousands made him more nervous and afraid than his historic flight. As he reached the podium, the awaiting Valya tearfully whispered in his ear, "Our dream has come true, Yuri." Embracing her he replied, "You're a smart girl! Thank you!" [...]

Russian Archives Online

Disponível em: <http://www.russianarchives.com/gallery/gagarin/>. Acesso em: 19 mar. 2014. (Fragmento)

Rewrite some clauses from the text in just one sentence and set the chronological order for the events according to the text. The beginning of each sentence was given.

A) Yuri helped his parents dig a dugout where they lived / the war was over.

Before the war was over, __________________________________________________________

______________________________________________________________________________

B) Yuri was subjected to extremely rigorous training / He underwent long periods in a sensory deprivation chamber. 

After Yuri had been subjected to extremely rigorous training ______________________________

______________________________________________________________________________

C) Senior Lieutenant Yuri Alexeyevich Gagarin orbited earth one time at an altitude of 187 3/4 miles (302 kilometers) for 108 minutes at 18,000 miles an hour / the first earthling escaped the gravity well of planet earth 

When Senior Lieutenant Yuri Alexeyevich Gagarin orbited earth ___________________________

______________________________________________________________________________

______________________________________________________________________________

D) He reached the podium / the awaiting Valya tearfully whispered in his ear: "Our dream has come true, Yuri." 

After he had reached the podium, ___________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Texto base:

Enunciado:

A) Que outra civilização da Antiguidade se assemelha a ela nas construções de pirâmides?

B) A utilização desses monumentos atendia às mesmas funções nas duas civilizações?

 Um laboratório está desenvolvendo um teste rápido para detectar a presença de determinado vírus na saliva. Para conhecer a acurácia do teste é necessário avaliá-lo em indivíduos sabidamente doentes e nos sadios. A acurácia de um teste é dada pela capacidade de reconhecer os verdadeiros positivos (presença de vírus) e os verdadeiros negativos (ausência de vírus). A probabilidade de o teste reconhecer os verdadeiros negativos é denominada especificidade, definida pela probabilidade de o teste resultar negativo, dado que o indivíduo é sadio. O laboratório realizou um estudo com 150 indivíduos e os resultados estão no quadro.

Considerando os resultados apresentados no quadro, a especificidade do teste da saliva tem valor igual:

Durante um surto de gripe, 25% dos funcionários de uma empresa contraíram essa doença. Dentre os que tiveram gripe, 80% apresentaram febre. Constatou-se também que 8% dos funcionários apresentaram febre por outros motivos naquele período. Qual a probabilidade de que um funcionário dessa empresa, selecionado ao acaso, tenha apresentado febre durante o surto de gripe?