Plane Geometry
-  If ∆PQR and ∆LMN are similar and 3PQ = LM and MN = 9 cm, then QR is equal to :
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                        View Hint View Answer Discuss in Forum As per the given in question , we draw figures of two similar triangles PQR and LMN  
 Here , 3PQ = LM and MN = 9 cm
 ∆ PQR ~ ∆ LMN∴ PQ = QR LM MN ⇒ PQ = QR 3PQ 9 
 Correct Option: DAs per the given in question , we draw figures of two similar triangles PQR and LMN  
 Here , 3PQ = LM and MN = 9 cm
 ∆ PQR ~ ∆ LMN∴ PQ = QR LM MN ⇒ PQ = QR 3PQ 9 ⇒QR = 1 × 9 = 3 cm. 3 
-  The perimeter of two similar triangles ABC and PQR are 36 cms and 24 cms respectively. If PQ = 10 cm then the length of AB is
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                        View Hint View Answer Discuss in Forum Given that , The perimeter of two triangles ABC and PQR are 36 cms and 24 cms. and PQ = 10 cm 
 ∆ ABC ~ ∆ PQR∴ AB = BC = AC PQ QR PR = AB + BC + AC PQ + QR + PR ⇒ AB = 36 ⇒ AB = 3 PQ 24 10 2 
 Correct Option: CGiven that , The perimeter of two triangles ABC and PQR are 36 cms and 24 cms. and PQ = 10 cm 
 ∆ ABC ~ ∆ PQR∴ AB = BC = AC PQ QR PR = AB + BC + AC PQ + QR + PR ⇒ AB = 36 ⇒ AB = 3 PQ 24 10 2 ⇒ AB = 3 × 10 = 15 cm. 2 
-  Which of the following is a true statement?
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                        View Hint View Answer Discuss in Forum If the corresponding sides of two triangles be proportional, the triangles are similar. Correct Option: CIf the corresponding sides of two triangles be proportional, the triangles are similar. Hence , option C is correct answer . 
-  The perimeter of two similar triangles ∆ABC and ∆PQR are 60 cm and 36 cm respectively. If PQ = 18 cm, then AB is :
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                        View Hint View Answer Discuss in Forum Here , The perimeter of two similar triangles ∆ABC and ∆PQR are 60 cm and 36 cm 
 and PQ = 18 cm
 ∆ ABC ~ ∆ PQR
 As we know that ,∴ AB = BC = CA PQ QR RP = AB + BC + CA PQ + QR + RP ⇒ AB = 60 PQ 36 ⇒ AB = 60 18 36 
 Correct Option: DHere , The perimeter of two similar triangles ∆ABC and ∆PQR are 60 cm and 36 cm 
 and PQ = 18 cm
 ∆ ABC ~ ∆ PQR
 As we know that ,∴ AB = BC = CA PQ QR RP = AB + BC + CA PQ + QR + RP ⇒ AB = 60 PQ 36 ⇒ AB = 60 18 36 ⇒ AB = 60 × 18 = 30 cm. 36 
-  Q is a point in the interior of a rectangle ABCD. If QA = 3 cm, QB = 4 cm and QC = 5 cm, then the length of QD (in cm) is
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                        View Hint View Answer Discuss in Forum According to question , we draw a figure of rectangle ABCD  
 Given that , QA = 3 cm, QB = 4 cm and QC = 5 cm,
 Using Pythagoras theorem,
 QD² + QB² = QA² + QC²
 ⇒ QD² + 16 = 9 + 25
 ⇒ QD² = 34 – 16 = 18Correct Option: AAccording to question , we draw a figure of rectangle ABCD  
 Given that , QA = 3 cm, QB = 4 cm and QC = 5 cm,
 Using Pythagoras theorem,
 QD² + QB² = QA² + QC²
 ⇒ QD² + 16 = 9 + 25
 ⇒ QD² = 34 – 16 = 18
 ⇒ QD = √18 = 3√2 cm
 
	