Answer:
5
Step-by-step explanation:
This shape is formed by two right triangles.
Let's start by the little one.
Let y be the third side.
Using the Pythagorian theorem we get:
y^2 = 6^2 + 3^2
y^2 = 36 + 9
y^2 = 45
y = 3√(5)
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Now let's focus on the second triangle. Let z be the third side.
The Pythagorian theorem:
6^2 + x^2 = z^2
Using the Pythagorian theorem on the big triangle :
[3√(5)]^2 + z^2 = (3+x)^2
45 + z^2 = 3x^2 + 6x + 9
36 +z^2 = 3x^2 +6x
So we have a system of equations.
36+ x^2 = z^2
36 +z^2 = 3x^2 +6x
We want to khow the value of x so we will eliminate z .
Add (36+x^2 -z^2 =0) to the second one.
36 + x^2-z^2+36+z^2 = 3x^2+6x
72 + x^2 = 3x^2 +6x
72 - 2x^2 -6x = 0
Multipy it by -1 to reduce the number of - signs
2x^2 + 6x -72 = 0
This is a quadratic equation
Let A be the discriminant
● a = 2
● b = 6
● c = -72
A = b^2-4ac
A = 36 -4*2*(-72) = 36 + 8*72 =612
So this equation has two solutions
The root square of 612 is approximatively 25.
● (-6-25)/4 = -31/4 = -7.75
● (-6+25)/4 = 19/4 = 4.75 wich is approximatively 5
A distance cannot be negative so x = 5
