1. **Problem Statement:** Given two wedges joined together, find the resultant wedge angle or combined effect. 2. **Formula and Explanation:** When two wedges with angles $\theta_1$ and $\theta_2$ are joined, the total wedge angle $\theta$ is the sum of the individual angles: $$\theta = \theta_1 + \theta_2$$ This is because wedge angles add linearly when wedges are placed side by side. 3. **Example:** Suppose wedge 1 has an angle of $15^\circ$ and wedge 2 has an angle of $25^\circ$. 4. **Calculation:** $$\theta = 15^\circ + 25^\circ = 40^\circ$$ 5. **Interpretation:** The combined wedge formed by joining these two wedges has an angle of $40^\circ$. This simple addition rule applies to wedges joined along their edges without overlap or gaps. **Final answer:** The resultant wedge angle is $40^\circ$.