Respuesta :
The sum of the measures of all interior angles in a quadrilateral is always equal to 360°.
If m∠R = (2x)°, m∠S = (3x – 35)° and m∠T = (x + 35)°, then the measure of the angle U is
m∠U=360°-(2x)°-(3x-35)°-(x+35)°=360°-(2x)°-(3x)°+35°-x°-35°=360°-(6x)°.
If quadrilateral RSTU is parallelogram, then
- m∠R=m∠T;
- m∠S=m∠U;
- m∠R+m∠S=m∠S+m∠T=180°.
Check this conditions: 2x=x+35 ⇒ x=35°.
If x=35°, then
- m∠R=(2·35)°=70°;
- m∠S=(3·35-35)°=70°;
- m∠T=(35+35)°=70°;
- m∠U=360°-(6·35)°=150°.
You get quadrilateral RSTU that cannot be parallelogram, because 70°+70°≠180°.
Answer: strictly correct choice is D (also choice C is correct)
Prallelogram has 2 pairs of opposite sides as parallel. The quadrilateral RSTU can not be a parallelogram.
What is parallelogram?
A parallelogram is a quadrilateral whose opposite sides are of equal length and the pair of opposite sides are parallel to each other.
We know that the sum of all the angles of a quadrilateral is 360°, therefore, in quadrilateral RSTU, the measure of ∠U can be written as,
∠R + ∠S + ∠T + ∠U = 360°
Substitute the values, ∠R = (2x)°, ∠S = (3x – 35)°, and ∠T = (x + 35)°,
(2x) + (3x – 35) + (x + 35) + ∠U = 360°
2x + 3x - 35 + x +35 + ∠U = 360°
∠U = 360° - 6x
We know that for a quadrilateral to be a parallelogram the opposite sides must be equal, therefore,
∠R = ∠T
∠S = ∠U
Let's substitute the values and check,
∠R = ∠T
[tex]\angle R = \angle T\\2x = x +35\\2x-x = 35\\x =35[/tex]
∠S = ∠U
[tex]\angle S = \angle U\\3x-35 = 360 -6x\\3x+6x = 360+35\\x = 43.889[/tex]
As we can see that when the value of x is different in both the cases and if we put the value of x as 35, then all three given angles measure 70°. The fourth angle would measure 150°.
Hence, the quadrilateral RSTU can not be a parallelogram.
Learn more about Parallelogram:
https://brainly.com/question/1563728