Finding the Fourth Proportional to 1,870.81, 2,807.33 and 830.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,870.81 : 2,807.33 = 830.87 : x
2. Step 2: Convert to fraction form
   1,870.81/2,807.33 = 830.87/x
3. Step 3: Cross multiply
   1,870.81x = 2,807.33 × 830.87
4. Step 4: Simplify right side
   1,870.81x = 2,332,518.61
5. Step 5: Solve for x
   x = 2,332,518.61/1,870.81
6. Step 6: Final answer
   x = 1,246.80