To find the total weight of 4 cement blocks, we need to multiply the weight of one block by the number of blocks.
Each cement block weighs \( 3 \frac{3}{4} \) pounds.
First, convert \( 3 \frac{3}{4} \) into an improper fraction:
\[ 3 \frac{3}{4} = \frac{3 \times 4 + 3}{4} = \frac{12 + 3}{4} = \frac{15}{4} \]
Now, multiply this by 4:
\[ 4 \times \frac{15}{4} \]
The \( 4 \) in the numerator and denominator cancels out:
\[ = \frac{15 \times 4}{4} = 15 \]
So, the total weight of 4 cement blocks is \( 15 \) pounds.
Thus, the answer is:
\[ 15 \text{ pounds} \]