The golden ratio is a special number approximately equal to 1.618 that appears often in mathematics,

geometry, art, architecture and other areas.
Given that the numbers 10 and x are in a golden ratio and that x is larger than 10, determine the exact
value of x. Only algebraic solutions will get full marks.

User Icon for Anonymous Anonymous answered
3 years ago

if a>b

then works if
(a+b) / a = a / b
here a = x and b = 10
so
(x+10) /x = x / 10
10 (x+10) = x^2
10 x + 100 = x^2
x^2 - 10 x -100 = 0
x = [ 10 +/- sqrt(100 + 400) ] / 2
use the + sign because x must be >10
x = [ 10 + sqrt 500 ] / 2 = (1/2) (10 + 10 sqrt 5) = 5 ( 1+sqrt 5)

User Icon for Anonymous Anonymous answered
3 years ago

sure enough, x is about 16.18033989

User Icon for Step-by-Step Bot Step-by-Step Bot answered
1 year ago

To determine the exact value of x in the golden ratio with the number 10, we can use the formula for the golden ratio.

The golden ratio is given by the equation:

x / 10 = (1 + √5) / 2

First, let's simplify the equation by cross-multiplying:

2x = 10 * (1 + √5)

Next, distribute the 10:

2x = 10 + 10√5

Now, let's isolate x by subtracting 10 from both sides:

2x - 10 = 10√5

Then, divide both sides by 2:

x - 5 = 5√5

Finally, add 5 to both sides to solve for x:

x = 5 + 5√5

Therefore, the exact value of x in the golden ratio with the number 10 is:

x = 5 + 5√5

User Icon for Explain Bot Explain Bot answered
11 months ago

To find the exact value of x, we need to use the definition of the golden ratio. The golden ratio states that the ratio of a larger quantity (x) to a smaller quantity (10) is equal to the ratio of the sum of the two quantities (x + 10) to the larger quantity (x).

Mathematically, this can be expressed as:

x / 10 = (x + 10) / x

To solve this equation, we can start by cross-multiplying:

x * x = 10 * (x + 10)

Simplifying further:

x^2 = 10x + 100

Rearranging the equation:

x^2 - 10x - 100 = 0

Now, we have a quadratic equation. To solve it, we can use the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / (2a)

For our equation, a = 1, b = -10, and c = -100. Substituting these values into the formula:

x = (-(-10) ± √((-10)^2 - 4 * 1 * -100)) / (2 * 1)
= (10 ± √(100 + 400)) / 2
= (10 ± √500) / 2

To simplify the radical, we can break down 500 into its factors:

x = (10 ± √(100 * 5)) / 2
= (10 ± √100 * √5) / 2
= (10 ± 10√5) / 2
= 10/2 ± 10√5/2
= 5 ± 5√5

Therefore, the two possible values of x in the golden ratio with 10 (where x is larger than 10) are:

x = 5 + 5√5
or
x = 5 - 5√5