Given that the triangles in the diagram are congruent and $mF$ = $40°$, what is the measure of angle $G$ in the congruent triangle?

• A. $140°$
• B. $80°$
• C. $40°$
• D. $50°$

Answer: (C)

Verified step by step guidance

1. Identify that the two triangles are congruent, which means all corresponding angles and sides are equal.
2. Note the given measure of angle F is \(40^\circ\) in one triangle.
3. Recall that the sum of interior angles in any triangle is \(180^\circ\), so use the formula \(\text{angle A} + \text{angle B} + \text{angle C} = 180^\circ\) to relate the angles.
4. Use the given angles (such as \(140^\circ\) and \(80^\circ\) if they correspond to the other triangle) to find the missing angle by subtracting the sum of the known angles from \(180^\circ\).
5. Since the triangles are congruent, the measure of angle G in the second triangle will be equal to the corresponding angle in the first triangle, which you find from the previous step.