ICSE-VIII-Mathematics

17: Special Types of Quadrilaterals Class 8 Maths

with Solutions -
  • #4
    In square PQRS : (i) if PQ = 3x - 7 and QR = x + 3 ; find PS (ii) if PR = 5x and QR = 9x - 8. Find QS (i) if PQ = 3x - 7 and QR = x + 3 ; find PS (ii) if PR = 5x and QR = 9x - 8. Find QS
    Ans : (i) sides of square are equal.

    PQ = QR
    ⇒ 3x - 7 = x + 3
    ⇒ 3x - x = 3 + 7
    ⇒ 2x = 10
    ⇒ x = 5
    PS = PQ = 3x - 7 = 3×5 - 7 =8 (ii) PR = 5x and QS = 9x - 8

    As diagonals of square are equal.
    PR = QS
    5x = 9x - 8
    ⇒ 5x - 9x = -8
    ⇒ -4x = -8
    ⇒ x = 2
    QS = 9x - 8 = 9 ×2 - 8 = 10 (i) sides of square are equal.

    PQ = QR
    ⇒ 3x - 7 = x + 3
    ⇒ 3x - x = 3 + 7
    ⇒ 2x = 10
    ⇒ x = 5
    PS = PQ = 3x - 7 = 3×5 - 7 =8 (ii) PR = 5x and QS = 9x - 8

    As diagonals of square are equal.
    PR = QS
    5x = 9x - 8
    ⇒ 5x - 9x = -8
    ⇒ -4x = -8
    ⇒ x = 2
    QS = 9x - 8 = 9 ×2 - 8 = 10
  • #4-i
    if PQ = 3x - 7 and QR = x + 3 ; find PS
    Ans : sides of square are equal.

    PQ = QR
    ⇒ 3x - 7 = x + 3
    ⇒ 3x - x = 3 + 7
    ⇒ 2x = 10
    ⇒ x = 5
    PS = PQ = 3x - 7 = 3×5 - 7 =8
  • #4-ii
    if PR = 5x and QR = 9x - 8. Find QS
    Ans : PR = 5x and QS = 9x - 8

    As diagonals of square are equal.
    PR = QS
    5x = 9x - 8
    ⇒ 5x - 9x = -8
    ⇒ -4x = -8
    ⇒ x = 2
    QS = 9x - 8 = 9 ×2 - 8 = 10