332 Listen again and choose the correct answers. 1 Juliet studies at home because her parents... a are - id1826913820220208 от hatira801 08.02.2022 09:40

Question

Геометрия: 332 Listen again and choose the correct answers. 1 Juliet studies at home because her parents... a are both tutors. b prefer home-schooling, c didn t want her to go to the local school 2 What does Larry dislike about his school? a There are no girls. b There are strict rules. He has to wear a uniform. 3 Larry thinks that classes should be mixed because ... a students are happier in mixed classes. b girls and boys are together in real life. C exam results are better in mixed schools. 4 Wayne must

hatira801 · Accepted Answer

Проекция ребра SA  на плоскость будет OA (SO ┴ (ABCDEF)  и  равна радиусу описанной около основания (здесь правильного шестиугольника) , что свою очередь равна сторону шестиугольника a₆ = R =acosα ; SO =H =asinα .
Vпир =1/3*Sосн*H =1/3*6*√3/4*(acosα)²*asinα =(√3/2)*cos²α*sinα*a³ .
  При α=60° ; a= 2 получаем :   Vпир = (√3/2)*1/4*(√3/2*8 =3/2.
  Апофема   пирамиды  является образующий  конуса
Vкон =1/3*π*r² *H
r = (√3/2)*R =(√3/2)*acosα.
Vкон  =1/3*π*((√3/2)*acosα)*asinα =.(π/4)*cos²α*sinα*a³ .
Получилось Vкон = ( π/2√3) *Vпир  .
При α=60° ; a= 2 получаем : Vкон =( π/2√3)*3/2 =π√3/6.

L =√(a² - (R/2)² =√(a² -(1/2*acosα)²) =a/2*√(4 - cos²α) ;

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