Предмет: Геометрия, автор: hanaru1

діагональ осьового перерізу зрізаного конуса дорівнює 10 см, радіус основ - 2 см і 4 см. Обчисліть площу осьового перерізу зрізаного конуса. Помогите решить.


kirichekov: в осевом сечении конуса не может быть диагонали, т.к. осевое сечение конуса- треугольник
kirichekov: теперь правильное условие

Ответы

Автор ответа: kirichekov
14
осевое сечение конуса равнобедренная трапеция
S=(a+b)*h/2
a=2см, b=4 см, h-?
СМ и ВК высоты трапеции
АК=МД=(4-2)/2
МД=1 см
прямоугольный ΔАМС: по теореме Пифагора 
АС²=АМ²+СМ²
10²=1²+СМ²,  СМ²=99
СМ=3√11 см
h=3√11
S=(2+4)*3√11/2
S=9√11 см²
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