Question

1. half of the diameter of a circle is called the what? 19. solve $1\frac{1}{4}\div2\frac{1}{2}$

Explanation:

Step1: Convert mixed numbers to improper fractions

$1\frac{1}{4}=\frac{1\times4 + 1}{4}=\frac{5}{4}$，$2\frac{1}{2}=\frac{2\times2+1}{2}=\frac{5}{2}$

Step2: Divide the fractions

$\frac{5}{4}\div\frac{5}{2}=\frac{5}{4}\times\frac{2}{5}$

Step3: Simplify the expression

$\frac{5\times2}{4\times5}=\frac{10}{20}=\frac{1}{2}$

Answer:

$\frac{1}{2}$