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Finding the Fourth Proportional to 753.72, 1,128.96 and 428.10

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Solution

The fourth proportional to 753.72, 1,128.96 and 428.10 is: 641.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    753.72 : 1,128.96 = 428.10 : x
  2. Step 2: Convert to fraction form
    753.72/1,128.96 = 428.10/x
  3. Step 3: Cross multiply
    753.72x = 1,128.96 × 428.10
  4. Step 4: Simplify right side
    753.72x = 483,307.78
  5. Step 5: Solve for x
    x = 483,307.78/753.72
  6. Step 6: Final answer
    x = 641.23

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.