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Date November 2016 Marks available 2 Reference code 16N.2.SL.TZ0.T_5
Level Standard Level Paper Paper 2 Time zone Time zone 0
Command term Calculate Question number T_5 Adapted from N/A

Question

A farmer owns a plot of land in the shape of a quadrilateral ABCD.

AB = 105  m, BC = 95  m, CD = 40  m, DA = 70  m and angle DCB = 90 .

N16/5/MATSD/SP2/ENG/TZ0/05

The farmer wants to divide the land into two equal areas. He builds a fence in a straight line from point B to point P on AD, so that the area of PAB is equal to the area of PBCD.

Calculate

the length of BD;

[2]
a.

the size of angle DAB;

[3]
b.

the area of triangle ABD;

[3]
c.

the area of quadrilateral ABCD;

[2]
d.

the length of AP;

[3]
e.

the length of the fence, BP.

[3]
f.

Markscheme

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

( BD = )   95 2 + 40 2    (M1)

 

Note:     Award (M1) for correct substitution into Pythagoras’ theorem.

 

= 103   ( m )   ( 103.077 ,   25 17 )    (A1)(G2)

[2 marks]

a.

cos B A ^ D = 105 2 + 70 2 ( 103.077 ) 2 2 × 105 × 70      (M1)(A1)(ft)

 

Note:     Award (M1) for substitution into cosine rule, (A1)(ft) for their correct substitutions. Follow through from part (a).

 

( B A ^ D ) = 68.9   ( 68.8663 )    (A1)(ft)(G2)

 

Note:     If their 103 used, the answer is  68.7995

 

[3 marks]

b.

( Area of ABD = ) 1 2 × 105 × 70 × sin ( 68.8663 )    (M1)(A1)(ft)

 

Notes:     Award (M1) for substitution into the trig form of the area of a triangle formula.

Award (A1)(ft) for their correct substitutions.

Follow through from part (b).

If 68.8° is used the area = 3426.28   m 2 .

 

= 3430   m 2   ( 3427.82 )    (A1)(ft)(G2)

[3 marks]

c.

area of ABCD = 1 2 × 40 × 95 + 3427.82    (M1)

 

Note:     Award (M1) for correctly substituted area of triangle formula added to their answer to part (c).

 

= 5330   m 2   ( 5327.83 )    (A1)(ft)(G2)

[2 marks]

d.

1 2 × 105 × AP × sin ( 68.8663 ) = 0.5 × 5327.82    (M1)(M1)

 

Notes:     Award (M1) for the correct substitution into triangle formula.

Award (M1) for equating their triangle area to half their part (d).

 

( AP = )   54.4   ( m )   ( 54.4000 )    (A1)(ft)(G2)

 

Notes:     Follow through from parts (b) and (d).

 

[3 marks]

e.

B P 2 = 105 2 + ( 54.4000 ) 2 2 × 105 × ( 54.4000 ) × cos ( 68.8663 )    (M1)(A1)(ft)

 

Notes:     Award (M1) for substituted cosine rule formula.

Award (A1)(ft) for their correct substitutions. Accept the exact fraction 53 147 in place of cos ( 68.8663 ) .

Follow through from parts (b) and (e).

 

( BP = )   99.3   ( m )   ( 99.3252 )    (A1)(ft)(G2)

 

Notes:     If 54.4 and cos ( 68.9 ) are used the answer is  99.3567

 

[3 marks]

f.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.
[N/A]
d.
[N/A]
e.
[N/A]
f.

Syllabus sections

Topic 3—Geometry and trigonometry » SL 3.2—2d and 3d trig
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Topic 3—Geometry and trigonometry

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