Question : In $\Delta$PQR, $\angle$P : $\angle$Q : $\angle$R = 2 : 2 : 5. A line parallel to QR is drawn which touches PQ and PR at A and B respectively. What is the value of $\angle$PBA – $\angle$PAB?
Option 1: 60º
Option 2: 30º
Option 3: 20º
Option 4: 50º
Correct Answer: 60º
Solution :
In a triangle, the angles are in the ratio 2 : 2 : 5. Let the angles are $2x$, $2x$, and $5x$ respectively, where $x$ is a constant. Since the sum of the angles in a triangle is \(180^\circ\). $⇒2x + 2x + 5x = 180^\circ$ $⇒x = 20^\circ$ $\angle P = \angle Q = 40^\circ$ and $\angle R = 100^\circ$. Since a line AB parallel to QR is drawn which touches PQ and PR at A and B, by the corresponding angles theorem. $⇒\angle PAB = \angle Q = 40^\circ$ and $\angle PBA = \angle R = 100^\circ$. $⇒\angle PBA - \angle PAB = 100^\circ - 40^\circ = 60^\circ$ Hence, the correct answer is 60º.
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Question : In a $\triangle P Q R, \angle P: \angle Q: \angle R=3: 4: 8$. The shortest side and the longest side of the triangle, respectively, are:
Option 1: PQ and PR
Option 2: QR and PR
Option 3: PQ and QR
Option 4: QR and PQ
Question : In $\Delta PQR,$ $\angle P : \angle Q : \angle R = 1: 3 : 5$, what is the value of $\angle R - \angle P$?
Option 1: $30^\circ$
Option 2: $80^\circ$
Option 3: $45^\circ$
Option 4: $60^\circ$
Question : In a $\triangle \mathrm{PQR}$ and $\triangle\mathrm{ABC}$, $\angle$P = $\angle$A and AC = PR. Which of the following conditions is true for $\triangle$PQR and $\triangle$ABC to be congruent?
Option 1: AB = PQ by SSS
Option 2: AB = PQ by SAS
Option 3: BC = QR by ASS
Option 4: $\angle$Q = $\angle$B by AAA
Question : If $\triangle$PQR is right-angled at Q, PQ = 12 cm and $\angle$PRQ = 30°, then what is the value of QR?
Option 1: $12\sqrt{3}$
Option 2: $12\sqrt2$
Option 3: $12$
Option 4: $24$
Question : ΔPQR is right angled at Q such that PQ = ( x - y ), QR = x, and PR = ( x + y ). S is a point on QR such that QS = PQ. The ratio QS : SR for any values of x and y is:
Option 1: 3 : 1
Option 2: 2 : 1
Option 3: 1 : 2
Option 4: 1 : 3
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