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Mathematics · Oct / Nov 2024 · Paper 11 · Question 5

YMA01

As printed in the paper

The question as text

5. A plot of land OAB is in the shape of a sector of a circle with centre O. Given • OA = OB = 5 km • angle AOB = 1.2 radians

Read automatically from the paper; the printed page above is exact.

Show the answer and mark scheme
  • 5(a)[2]

    Perimeter =5 + 5 + 6 = 16 (km)

    1

    1

    2

    2

  • 5(b)[3]

    Attempts

    r

    θ

    =

    ×

    5

    ×

    1.2

    2

    2

    1

    1

    2

    2

    Area AOP =

    ×

    ×

    5

    ×

    1.2

    =

    3.75 km

    *

    4

    2

    Sets 1

    ××

    5

    OP

    ×

    sin1.2

    =

    3.75

    OP

    =

    ...

  • 5(c)[4]

    2

    OP =

    1.6...

    2

    2

    2

    AP =

    5

    +

    "1.6.."

    −××

    2 5 "1.6.." cos1.2

    ×

    AP =

    4.7km

    or

    4700m

    (a)

    M1: Attempts

    5 1.2

    r

    θ

    = ×

    A1: Achieves 16 (km)

    (b)

    1

    1

    (or 1

    1

    2

    2

    M1: Attempts

    r

    θ

    =

    ×

    5

    ×

    1.2

    rl =

    ××

    5 6

    ) May be implied by Area of sector =

    2

    2

    2

    2

    15 seen.

    1

    1

    3

    1

    2

    2

    M1: Attempts

    ×

    ×

    5

    ×

    1.2

    or

    ×

    ×

    5

    ×

    1.2

    or other full method to find the area for

    4

    2

    4

    2

    one of the two regions.

    A1*: Achieves given answer, including units, showing all steps with no errors and full

    accuracy kept throughout. Score A0 if rounded values were used during working.

    Approaches by verification are acceptable. The first M1 will apply the same way, a clear

    attempt at the sector area formula will be needed to determine the area.

    The second M may then be gained for attempting

    Then for the A mark the calculations need to both be correct (giving 15), and a

    conclusion made: E.g. (so) Area R2 = 3.75 km2.

    (c)

    M1: Sets 1

    ××

    5

    OP

    ×

    sin1.2

    =

    3.75

    OP

    =

    ...

    There are some longer methods to find OP, so

    2

    this may be scored for any complete method. E.g finds area of triangle APB from

    1 5

    2 sin1

    difference of area triangle OAB

    =

    .2

    and 3.75, the uses ratio OP:PB is same

    2

    Let X be base of perpendicular to OA though P, then

    1

    "1.5"

    5

    XP

    3.75

    XP

    1.5

    OX

    so

    ××

    =

    =

    =

    2

    tan1.2

    5(c) Alt

    "1.5"

    AX =

    5

    −

    =

    ...

    tan1.2

    AX =

    4.416...

    2

    2

    2

    AP =

    "4.416..."

    +

    "1.5"

    =

    ...

    AP =

    4.7km

    or

    4700m

    x =

    2

    1

    1/x type shape

    2

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