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Finding the Fourth Proportional to 866.78, 1,300.16 and 318.75

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Solution

The fourth proportional to 866.78, 1,300.16 and 318.75 is: 478.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    866.78 : 1,300.16 = 318.75 : x
  2. Step 2: Convert to fraction form
    866.78/1,300.16 = 318.75/x
  3. Step 3: Cross multiply
    866.78x = 1,300.16 × 318.75
  4. Step 4: Simplify right side
    866.78x = 414,417.91
  5. Step 5: Solve for x
    x = 414,417.91/866.78
  6. Step 6: Final answer
    x = 478.11

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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.