1. Step 1 Draw a line segment AB of 5 cm. Taking A and B as centre, draw arcs of 6 cm and 5 cm radius respectively. Let these arcs intersect each other at point C. ΔABC is the required triangle having length of sides as 5 cm, 6 cm, and 7 cm respectively. Step 2 Draw a ray AX making acute angle with linRead more

    Step 1
    Draw a line segment AB of 5 cm. Taking A and B as centre, draw arcs of 6 cm and 5 cm radius respectively.
    Let these arcs intersect each other at point C. ΔABC is the required triangle having length of sides as 5 cm, 6 cm, and 7 cm respectively.
    Step 2
    Draw a ray AX making acute angle with line AB on the opposite side of vertex C.
    Step 3
    Locate 7 points, A₁, A₂, A₃, A₄, A₅, A₆, A₇, (as 7 is greater between 5 and 7), on line AX such that AA₁ = A₁A₂ = A₂A₃ = A₃A₄ = A₄A₅ = A₅A₆ = A₆A₇.
    Step 4
    Join BA₅ and draw a line through A₇ parallel to BA₅ to intersect extended line segment AB at point B’.
    Step 5
    Draw a line through B’ parallel to BC intersecting the extended line segment AC at C’ ΔAB’C’ is the required triangle.
    Justification
    The construction can be justified by proving that
    AB’ = 7/5 AB, B’C’ = 7/5 BC, AC’ = 7/5 AC
    In ΔABC and Δ AB’C’,
    ∠ABC = ∠AB’C’ (Corresponding angles)
    ∠BAC = ∠B’AC’ (common)
    ∴ ΔABC ∼ ΔAB’C’ (AA similarity Criterion)
    ⇒ AB’/AB = B’C’/BC = AC’/AC …(1)
    In ΔAA₅B/AA₇B’,
    ∠A₅AB = ∠A₇AB’ (common)
    ∠AA₅B = ∠AA₇B'(Corresponding angles)
    ∴ ΔAA₅B ∼ ΔAA₇B’ (AA similarity criterion)
    ⇒ AB’/AB = AA₅/AA₇ ⇒ AB’/AB = 5/7 …(2)
    On comparing equations (1) and (2), we obtain.
    AB’/AB = B’C’/BC = AC’/AC = 7/5
    ⇒ AB’ = 7/5 AB, B’C’ = 7/5 BC, AC’ = 7/5 AC
    This justifies the construction.

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  2. Let O be the centre of the circle. Given: OQ = 25 cm and PQ = 24 CM We Know that the radius is perpendicular to tangent. Therefore, OP ⊥PQ In ΔOPQ, by pythagoras theorem, OP² + 24² = 25² ⇒ OP² = 625 - 576 ⇒ OP² = 49 ⇒OP = 7 Therefore, the radius of circle is 7 cm. Hence, the option (A) is correct.

    Let O be the centre of the circle.
    Given: OQ = 25 cm and PQ = 24 CM
    We Know that the radius is perpendicular to tangent. Therefore, OP ⊥PQ
    In ΔOPQ, by pythagoras theorem,
    OP² + 24² = 25² ⇒ OP² = 625 – 576 ⇒ OP² = 49 ⇒OP = 7
    Therefore, the radius of circle is 7 cm. Hence, the option (A) is correct.

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  3. Given: TQ and TP are two tangents of the circle. We know that the radius is perpendicular to tangent. Therefore, OP ⊥TP and OQ TQ. ⇒ ∠OPT = 90° and ∠OQT = 90° In quadrilaterral POQT, OQT + OQT + PTQ = 360° ⇒ 90° + 110° + 90° + ∠PTQ = 360° ⇒ ∠PTQ = 360° - 290° = 70 Hence, the option (B) is correct.

    Given: TQ and TP are two tangents of the circle.
    We know that the radius is perpendicular to tangent. Therefore, OP ⊥TP and OQ TQ.
    ⇒ ∠OPT = 90° and ∠OQT = 90°
    In quadrilaterral POQT, OQT + OQT + PTQ = 360°
    ⇒ 90° + 110° + 90° + ∠PTQ = 360°
    ⇒ ∠PTQ = 360° – 290° = 70
    Hence, the option (B) is correct.

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  4. Given: PA and PB are two tangents of the circle. We know that the radius is perpendicular to tangent. Therefore, OA ⊥PA and OB PB. ⇒ ∠OBP = 90° and ∠OAP = 90° In quadrilaterral AOBP, ∠OAP + ∠APB + ∠PBO + ∠BOA = 360° ⇒ 90° + 80° + 90° + ∠BOA = 360° ⇒ ∠BOA = 360° - 260° = 100° In ΔOPB and ΔOPA, AP = BRead more

    Given: PA and PB are two tangents of the circle.
    We know that the radius is perpendicular to tangent. Therefore, OA ⊥PA and OB PB.
    ⇒ ∠OBP = 90° and ∠OAP = 90°
    In quadrilaterral AOBP, ∠OAP + ∠APB + ∠PBO + ∠BOA = 360°
    ⇒ 90° + 80° + 90° + ∠BOA = 360°
    ⇒ ∠BOA = 360° – 260° = 100°
    In ΔOPB and ΔOPA,
    AP = BP [Tangents drawn from same external point]
    OA = OB [Radii]
    OP = OP [Common]
    Therefore, ΔOPB ≅ ΔOPA [SSS Congruency rule]
    Hence, ∠POB = ∠POA
    ∠POA = 1/2 ∠AOB = 1/2(100°) = 50°. Hence, the option (A) is correct.

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  5. Let AB is diameter, PQ and RS are tangents drawn at ends of diameter. We Know that the radius is perpendicular to tangent. therefore, OP ⊥PQ. ∠OAR = 90° and OAS = 90° ∠OBP = 90° and ∠OBQ = 90° From the above, we have ∠OAR = ∠OBQ [Alternate angles] ∠OAS = ∠OBP [Alternate angles] Since, alternate anglRead more

    Let AB is diameter, PQ and RS are tangents drawn at ends of diameter.
    We Know that the radius is perpendicular to tangent. therefore, OP ⊥PQ.
    ∠OAR = 90° and OAS = 90°
    ∠OBP = 90° and ∠OBQ = 90°
    From the above, we have
    ∠OAR = ∠OBQ [Alternate angles]
    ∠OAS = ∠OBP [Alternate angles]
    Since, alternate angles are equal. Hence, PQ is parallel to PS.

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