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Finding the Fourth Proportional to 785.17, 1,177.17 and 420.40

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Solution

The fourth proportional to 785.17, 1,177.17 and 420.40 is: 630.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.17 : 1,177.17 = 420.40 : x
  2. Step 2: Convert to fraction form
    785.17/1,177.17 = 420.40/x
  3. Step 3: Cross multiply
    785.17x = 1,177.17 × 420.40
  4. Step 4: Simplify right side
    785.17x = 494,882.27
  5. Step 5: Solve for x
    x = 494,882.27/785.17
  6. Step 6: Final answer
    x = 630.29

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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.