Answer:
Δ QRS ≈ Δ QST ≈ Δ SRT ⇒ 3rd answer
Step-by-step explanation:
From the given figure
In Δ QRS
∵ m∠S = 90°
∵ m∠S = m∠QST + m∠RST
∴ m∠QST + m∠RST = 90° ⇒ (1)
- Use the fact the sum of the measures of the interior angles
of a Δ is 180°
∴ m∠Q + m∠S + m∠R = 180°
∵ m∠S = 90
∴ m∠Q + 90° + m∠R = 180°
- Subtract 90 from both sides
∴ m∠Q + m∠R = 90° ⇒ (2)
In Δ QST
∵ m∠QTS = 90°
- By using the fact above
∴ m∠Q + m∠QST = 90 ⇒ (3)
- From (1) and (3)
∴ m∠QST + m∠RST = m∠Q + m∠QST
- Subtract m∠QST from both sides
∴ m∠RST = m∠Q
In Δ SRT
∵ m∠STR = 90°
- By using the fact above
∴ m∠R + m∠RST = 90 ⇒ (4)
- From (1) and (4)
∴ m∠QST + m∠RST = m∠R + m∠RST
- Subtract m∠RST from both sides
∴ m∠QST = m∠R
In Δs QRS and QST
∵ m∠S = m∠QTS ⇒ right angles
∵ m∠R = m∠QST ⇒ proved
∵ ∠Q is a common angle in the two Δs
∴ Δ QRS ≈ Δ QST ⇒ AAA postulate of similarity
In Δs QRS and SRT
∵ m∠S = m∠STR ⇒ right angles
∵ m∠Q = m∠RST ⇒ proved
∵ ∠R is a common angle in the two Δs
∴ Δ QRS ≈ Δ SRT ⇒ AAA postulate of similarity
If two triangles are similar to one triangle, then the 3 triangles are similar
∵ Δ QRS ≈ Δ QST
∵ Δ QRS ≈ Δ SRT
∴ Δ QRS ≈ Δ QST ≈ Δ SRT
