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Finding the Fourth Proportional to 805.48, 1,113.80 and 639.40

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Solution

The fourth proportional to 805.48, 1,113.80 and 639.40 is: 884.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.48 : 1,113.80 = 639.40 : x
  2. Step 2: Convert to fraction form
    805.48/1,113.80 = 639.40/x
  3. Step 3: Cross multiply
    805.48x = 1,113.80 × 639.40
  4. Step 4: Simplify right side
    805.48x = 712,160.52
  5. Step 5: Solve for x
    x = 712,160.52/805.48
  6. Step 6: Final answer
    x = 884.15

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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.