(a)        Draw the true shape of the laminae.
(b)        Measure and state the:
            (i)         angle of inclination to the horizontal plane;
            (ii)        true length of AC.
(c)        Indicate on the drawing, the:
            (i)         auxiliary elevation;
            (ii)        auxiliary plan.

Candidates were expected to:
(a)        (i)        COPY THE GIVEN VIEW:
                        (1)        draw the front elevation;
                        (2)        draw the plan;
                        (3)        draw the X – Y axis.
                        FIRST AUXILIARY ELEVATION:
(ii)        (1)        draw the horizontal line, A1D1 in the front elevation;
            (2)        project from D1 to D in  the plan;
            (3)        join AD and extend it beyond the X – Y axis;
(4)        draw parallel lines from B and C respectively to the line AD extended;

            (5)        draw X1Y1 axis perpendicular to AD extended;
(6)        locate B2, A2D2 and C2 using X – Y as datum with the corresponding dimensions from the elevation on X1 Y1 for the first auxiliary elevation;

(7)        draw the first auxiliary elevation.

            (iii)       TRUE SHAPE (SECOND AUXILIARY PLAN)

1. draw X2Y2  axis parallel to B2 C2 ;
2. locate A3, B3  and C3 use X 1 Y1  as the datum with the corresponding dimensions from the plan on X2Y2;
3. join the points A3, B3  and C3 to obtain the true shape.

(b)        Measure, indicate and state the:
            (i)         angle of inclination to the H.P =  590 ± 10 ;
            (ii)        true length of AC = 66 ± 1;

(c)        Indicate:
            (i)         auxiliary elevation;

 

The solution is shown below:

ALTERNATIVE METHOD
TRUE SHAPE OF TRIANGULAR LAMINAE
Candidates were expected:

1. (i)         COPY THE GIVEN VIEWS:

1. draw the front  elevation;
2. draw the plan;
3. draw the X – Y axis.

(ii)        TRUE SHAPE:

1. draw to obtain the true length AB;
2. draw to obtain the true length of AC;
3. using the true lengths to obtain the true shape.

1. (i)         Measure and state:
2. angle of inclination to the horizontal plane (HP) 59 ± 1;
3. true length of AC = 66 ± 1.

 

(c )       Indicate:

1. auxiliary elevation;
2. auxiliary plan (true shape).

   The solution is shown below: