The radius of a semicircle is 19 millimeters. What is the semicircle's area? r=19 mm
Use 3.14 for

2 1/2 inches

Explanation:

There are two marks on the line plot above 1 inch; both are on 1 1/4 inches.  This means to find the total length we add together

1 1/4 + 1 1/4

They already have a common denominator; this means we add the whole numbers then add the numerators.

1+1 = 2; 1/4 + 1/4 = 2/4

This gives us 2 2/4.  The fraction will simplify to 1/2; this gives us 2 1/2.