To find out the percentage of successful plays Christopher executed, we can set up a proportion based on the number of successful plays and the total number of plays.
Let \( x \) represent the percentage of successful plays. We know:
- Successful plays = 42
- Total plays = 60
We can set up the proportion as follows:
\[ \frac{\text{Successful Plays}}{\text{Total Plays}} = \frac{x}{100} \]
Substituting the known values into the equation, we get:
\[ \frac{42}{60} = \frac{x}{100} \]
Next, we can solve this proportion by cross-multiplying:
\[ 42 \cdot 100 = 60 \cdot x \]
This simplifies to:
\[ 4200 = 60x \]
Now, we can isolate \( x \) by dividing both sides by 60:
\[ x = \frac{4200}{60} \]
\[ x = 70 \]
Thus, the percentage of Christopher’s successful plays is:
\[ \boxed{70%} \]