Помогите решить, пожалуйста.

Question

Помогите решить, пожалуйста.

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Answer 1

P =AB+BC+AC = 1.6AC + 1.6AC + AC = 4.2AC
4.2AC = 21
AC = 5
AB = BC = 5*1.6 = 8

A=C => AB = BC
P = AB+BC+AC = 0.8AC+0.8AC+AC = 2.6AC
2.6AC = 7.8
AC = 3
AB = BC = 0.8AC = 2.4

Answer 2

1) Допустим AC = x, AB = 1.6 x, BC = 1.6x
P = 21, P = AC+AB+BC = 4.2x. 4.2x=21, x=5, AC = 5, AB = BC = 8
2) AC = X, AB = 0.8X = BC (равнобедренный треугольник).
P = 7.8. 7.8 = 2.6X, X = 3. AC = 3, AB = BC = 2.4