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Finding the Fourth Proportional to 1,128.57, 1,557.43 and 631.21

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Solution

The fourth proportional to 1,128.57, 1,557.43 and 631.21 is: 871.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.57 : 1,557.43 = 631.21 : x
  2. Step 2: Convert to fraction form
    1,128.57/1,557.43 = 631.21/x
  3. Step 3: Cross multiply
    1,128.57x = 1,557.43 × 631.21
  4. Step 4: Simplify right side
    1,128.57x = 983,062.84
  5. Step 5: Solve for x
    x = 983,062.84/1,128.57
  6. Step 6: Final answer
    x = 871.07

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.