In the USA and some other countries parents
sometimes take a role
of teachers and teach
Emn
DO YOU KNOW?
4 Read and answer the question below.
Ste
En
S
E
their children at
home. Why do
parents do this?
They don't like
regular schools.
They believe that there are too many students in the class
or that there is too much bullying. In other cases?, children
whose parents spend a lot of time travelling can't go to
regular schools. There are about 2,5 million children in the
USA whose parents are also their teachers.
ΔАВС-равносторонний 1) ВК - в равностороннем ΔАВС- является и
АВ=ВС=АС=9√3 высотой и медианой
ВК-биссектриса
Найти: ВК=? 2) рассмотрим ΔАВК-прямоугольный
АВ=9√3, АК=1\2 АС=1/2·9√3=4,5√3=9/2√3
3) По Т.Пифагора: ВК=√АВ²-АК²=
= √(9√3)²-(9/2√3)²=
= √81·3-81/4·3=√729/4=27/2=13,5
ответ: 13,5