ABCD is a rectangle with AB=50 and BC=120. E is a point on CD (possibly extended) such that AE=EC. What is the length of DE?

119

thanks

Let ABCD be a rectangle such that AB=5 and BC=12. There exist two distinct points X1 and X2 on BC such that ∠AX1D=∠AX2D=90∘. Suppose that d is the distance from X1 to X2. What is d2?

To find the length of DE, we need to use the properties of a rectangle and apply the Pythagorean theorem.

Step 1: Draw ABCD rectangle with given dimensions.

A__________B
| |
| |
| |
|____E_____C
D

Step 2: Since AE = EC, we can divide CD into two equal parts, making CE = ED.

A__________B
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| |
________E__|
D
C
Step 3: Apply the Pythagorean theorem to find the length of DE.

In the right triangle AED, we have AE = ED, AD = 50, and AD perpendicular to AE.

Using the Pythagorean theorem, where the hypotenuse (AD) is squared and equal to the sum of the squares of the other two sides:

AD^2 = AE^2 + ED^2

Since AE = ED, we can substitute AE for ED in the equation:

AD^2 = AE^2 + AE^2

Simplifying the equation:

AD^2 = 2 * AE^2

Now we can substitute the known values into the equation:

50^2 = 2 * AE^2

2500 = 2 * AE^2

Divide both sides of the equation by 2:

AE^2 = 1250

Taking the square root of both sides:

AE = sqrt(1250)

Therefore, the length of DE is equal to AE, so DE = sqrt(1250).