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Finding the Fourth Proportional to 784.78, 1,173.52 and 688.20

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Solution

The fourth proportional to 784.78, 1,173.52 and 688.20 is: 1,029.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.78 : 1,173.52 = 688.20 : x
  2. Step 2: Convert to fraction form
    784.78/1,173.52 = 688.20/x
  3. Step 3: Cross multiply
    784.78x = 1,173.52 × 688.20
  4. Step 4: Simplify right side
    784.78x = 807,616.46
  5. Step 5: Solve for x
    x = 807,616.46/784.78
  6. Step 6: Final answer
    x = 1,029.10

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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.