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Finding the Fourth Proportional to 763.50, 1,139.78 and 647.16

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Solution

The fourth proportional to 763.50, 1,139.78 and 647.16 is: 966.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    763.50 : 1,139.78 = 647.16 : x
  2. Step 2: Convert to fraction form
    763.50/1,139.78 = 647.16/x
  3. Step 3: Cross multiply
    763.50x = 1,139.78 × 647.16
  4. Step 4: Simplify right side
    763.50x = 737,616.79
  5. Step 5: Solve for x
    x = 737,616.79/763.50
  6. Step 6: Final answer
    x = 966.10

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.