QUESTION 11: TERMINOLOGY (DEVELOPMENT) (SPECIFIC) FIGURE 11 below shows a square-to-round transition piece - NSC Mechanical Technology Welding and Metalwork - Question 11 - 2020 - Paper 1

To calculate the length CI, we first determine the lengths CE and FH in triangle CEI:

1. Compute the length CE:

   $CE = CF - EF$

   Using CF = 400 mm and EF = 150 mm:

   $CE = 400 - 150 = 250 ext{ mm}$

2. Next, since EH = FH:

   $EH = HK = \frac{1}{\sqrt{3}} ext{ unit} = \frac{150}{\sqrt{3}}$

3. To find the total CI:

   $CI = \sqrt{CE^2 + FH^2}$

   Where FH = FK - HK:

   $FH = 400 - \frac{150}{\sqrt{3}} \approx 259.81 ext{ mm}$

4. Thus,

   $CI = \sqrt{(250)^2 + (140)^2} = \sqrt{62500 + 19600} \approx 286.62 ext{ mm}$

The true length JI is determined by calculating one twelfth of the circumference.

1. Start with the formula for circumference $C = \pi D$, where D is the diameter:

   For the circle corresponding to our figure, D = 800 mm.

   $C = \pi \cdot 800 \approx 2513.27 ext{ mm}$

2. Now calculate JI:

   $JI = \frac{1}{12} C$

   Thus,

   $JI = \frac{1}{12} \cdot 2513.27 \approx 209.44 ext{ mm}$