Activity 2: Find the fraction of shaded objects for each part. Simplify your answers.

There are 4 rows with 5 pentagons in each row.  
Total shapes = $4 \times 5 = 20$.

In each row, 3 pentagons are shaded.  
Number of shaded shapes = $4 \times 3 = 12$.

Fraction shaded = $\frac{\text{Number of shaded shapes}}{\text{Total number of shapes}} = \frac{12}{20}$.  
To simplify, divide both the numerator and the denominator by their greatest common divisor, which is 4.
$$
\frac{12 \div 4}{20 \div 4} = \frac{3}{5}
$$
The fraction of shaded shapes is $\boxed{\frac{3}{5}}$.

There are 4 rows with 6 circles in each row.  
Total shapes = $4 \times 6 = 24$.

In each row, 2 circles are shaded.  
Number of shaded shapes = $4 \times 2 = 8$.

Fraction shaded = $\frac{\text{Number of shaded shapes}}{\text{Total number of shapes}} = \frac{8}{24}$.  
To simplify, divide both the numerator and the denominator by their greatest common divisor, which is 8.
$$
\frac{8 \div 8}{24 \div 8} = \frac{1}{3}
$$
The fraction of shaded shapes is $\boxed{\frac{1}{3}}$.