Finding the Fourth Proportional to 1,059.12, 1,461.72 and 645.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,059.12 : 1,461.72 = 645.12 : x
2. Step 2: Convert to fraction form
   1,059.12/1,461.72 = 645.12/x
3. Step 3: Cross multiply
   1,059.12x = 1,461.72 × 645.12
4. Step 4: Simplify right side
   1,059.12x = 942,984.81
5. Step 5: Solve for x
   x = 942,984.81/1,059.12
6. Step 6: Final answer
   x = 890.35