Answer:
a) Since, [tex]\text{ 5.7 cm of thread} = \text{ 7.6 cm of fabric}[/tex]
⇒ [tex]\text{ 1 cm of thread} = \frac{7.6}{5.7}\text{ cm of fabric}[/tex]
⇒ [tex]\text{ 4.2 cm of thread} =\frac{7.6}{5.7}\times 4.2\text{ cm of fabric}[/tex]
⇒ [tex]\text{ 4.2 cm of thread} =\frac{31.92}{5.7}\text{ cm of fabric}[/tex]
⇒ [tex]\text{ 4.2 cm of thread} =5.6\text{ cm of fabric}[/tex]
Therefore, For 4.2 cm of thread, 5.6 cm of fabric involved.
b) Again,
[tex]7.6\text{ cm of fabric} = 5.7\text{ cm of thread}[/tex]
⇒ [tex]1\text{ cm of fabric} = \frac{5.7}{7.6}\text{ cm of thread}[/tex]
⇒ [tex]21.2\text{ cm of fabric} =\frac{5.7}{7.6}\times 21.2\text{ cm of thread}[/tex]
⇒ [tex]21.2\text{ cm of fabric} =\frac{120.84}{7.6}\text{ cm of thread}[/tex]
⇒ [tex]21.2\text{ cm of fabric} =15.9\text{ cm of thread}[/tex]
Therefore, For 21.2 cm of fabric, 15.9 cm of thread is used.
