Technical Drawing 2, May/June 2015

Question 4

(4) The figure above shows an irregular quadrilateral:

(a) copy, full size, the given view;

(b) (i) construct a square twice in area of the quadrilateral;

(ii) measure and state the length of the square.  

Observation

Candidates were expected to:

A.         COPY THE GIVEN VIEW

  1. draw the base PQ;
  2. draw PS at 105O to PQ;
  3. locate point R and complete the quadrilateral PQRS.

B.         CONVERT TO TRIANGLE

  1. produce PQ to a reasonable length;
  2. join SQ and RT parallel to SQ;
  3. complete triangle PTS.

 

C          CONVERT TO RECTANGLE

  1. drop perpendicular from S to V and bisect SV;
  2. draw rectangle PTMN.

 

 

D.            CONVERT TO SQUARE

  1. draw TL = TM;
  2. bisect  PL and draw semi-circle on PL;
  3. produce TM to F and draw square TFGH.

 

E.         ENLARGE SQUARE

                        Alternative A

  1. join FH;
  2. draw perpendiculars from H and F;
  3. complete the square FHJK.

 

OR
Alternative B

  1. draw perpendicular for H and make HD = HT;
  2. use T as centre and radius TD intercept PT produced at C;
  3. complete the square TABC.

 

F.         (i)         use correct scale 1:1;
(ii)         measure and state the length = 58 ± 1;
(iii)        draw neatly.

The solution is shown below.

  SIMILAR AREAS AND ENLARGEMENT

LENGTH OF SIDE OF ENLARGED SQUARE  =  58mm ±  1