СРОЧНО ЗАДАНИЕ ПО ГЕОМЕТРИИ УМОЛЯЮ ПОМОГИТЕ ПОЖАЛУЙСТА

1) с = 26
a : b = 5 : 12 = 5x : 12x
a^2 + b^2 = c^2
(5x)^2 + (12x)^2 = 26^2
169x^2 = 26^2
13x = 26
x = 2
a = 5x = 5*2 = 10
b = 12x = 2*12 = 24

2) a = 7
b
c = b + 7
a^2 + b^2 = c^2
7^2 + b^2 = (b + 7)^2
(b+7)^2 - b^2 = 7^2
((b+7) - b) * ((b+7) + b) = 7^2
7 * (2b+7) = 7^2
2b+7 = 7
2b = 1
b = 1
c = V(a^2 + b^2) = V(7^2 + 1^2) = V50 = 5V2
P = a + b + c = 7 + 1 + 5V2 = 8 + 5V2

3) tg a = sin a / cos a = 3/4
sin a = (3/4) * cos a
sin^2 a + cos^2 a = 1
((3/4)*cos a)^2 + cos^2 a = 1
cos^2 a * (9/16 + 1) = 1
cos^2 a * (9/16 + 16/16) = 1
cos a = 16/25 = 4/5
sin a = tg a * cos a = 3/4 * 4/5 = 3/5
cos^2 a = 14/

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