Answer:
RT = 7.1 cm
QR = 9 cm
∠QPR = 44°
∠STR = 92°
Step-by-step explanation:
Properties of an Isosceles Trapezoid
- Quadrilateral (2 dimensional, 4-sided shape)
- One pair of parallel sides (bases)
- One pair of non-parallel sides of equal length
- Diagonals are the same length
- Base angles are congruent
- Opposite angles are supplementary (sum to 180°)
- Sum of interior angles is 360°
One pair of non-parallel sides of equal length
Therefore:
Diagonals are the same length
- QS = PR = 12 cm
- QT = PT = 4.9 cm
⇒ RT = PR - PT
⇒ RT = 12 - 4.9
⇒ RT = 7.1 cm
Base angles are congruent
Therefore, ∠TSR = ∠TRS
Interior angles of a triangle sum to 180°
⇒ ∠TSR + ∠STR + ∠TRS = 180°
⇒ 44° + ∠STR + 44° = 180°
⇒ ∠STR = 92°
Using the Alternate Angles Theorem
⇒ ∠TSR = ∠PQT = 44°
As ∠PQT = ∠QPT and ∠QPT = ∠QPR then
⇒ ∠QPR = 44°