Explanation:
70°
Given, in \(\triangle\text{ABC},\angle\text{A}=40^\circ\) and \(\angle\text{B}=\angle\text{C}\)
Now, in a triangle,
\(\angle\text{A}+\angle\text{B}+\angle\text{C}=180\)
\(\Rightarrow\angle\text{A}+\angle\text{B}+\angle\text{C}=180\)
\(\Rightarrow\angle\text{A}+2\angle\text{C}=180\)
\(\Rightarrow40+2\angle\text{C}=180\)
\(\Rightarrow2\angle\text{C}=180-40\)
\(\Rightarrow2\angle\text{C}=140\)
\(\Rightarrow\angle\text{C}=\frac{140}{2}\)
\(\Rightarrow\angle\text{C}=70^\circ\)