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Finding the Fourth Proportional to 817.70, 1,128.28 and 538.40

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Solution

The fourth proportional to 817.70, 1,128.28 and 538.40 is: 742.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.70 : 1,128.28 = 538.40 : x
  2. Step 2: Convert to fraction form
    817.70/1,128.28 = 538.40/x
  3. Step 3: Cross multiply
    817.70x = 1,128.28 × 538.40
  4. Step 4: Simplify right side
    817.70x = 607,462.09
  5. Step 5: Solve for x
    x = 607,462.09/817.70
  6. Step 6: Final answer
    x = 742.90

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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.