Respuesta :

Definition of isos trapezoid=> A trapezoid with congruent legs.
Theorem=> Diagonals in a isosceles triangle are congreunt.
Answer=> SV is a diagonal and so is TU therefore they are equal.
Set aside=> 3x+1=x+21
Solve=> 2x=20
x=10

Answer:

The value of x is 10.

Step-by-step explanation:

Given information: STVU is an isosceles trapezoid, SV = 3x + 1 and TU = x + 21.

According to the properties of isosceles trapezoid, then diagonals of an isosceles trapezoid are equal.

SV and TU are diagonals of the isosceles trapezoid, so

[tex]SV=TU[/tex]

[tex]3x+1=x+21[/tex]

Separate like terms.

[tex]3x-x=21-1[/tex]

[tex]2x=20[/tex]

Divide both sides by 2.

[tex]x=10[/tex]

Therefore the value of x is 10.