Can you help me in this question?

Will used 20 colored tiles to make a design in art class. 5/20 of his tiles were red. what is an equivalent fraction for the red tiles?

What is the length of the unknown leg in the right triangle ?

A3cm×3cm\greend{3\,\text{cm} \times 3\,\text{cm}} 3cm×3cm start color greend, 3, space, c, m, times, 3, space, c, m, end color greend rectangle sits inside a circle with radius of 4cm\blued{4\,\text{cm}} 4cm start color blued, 4, space, c, m, end color blued . what is the area of the shaded region? round your final answer to the nearest hundredth.