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Finding the Fourth Proportional to 678.85, 1,017.49 and 312.87

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Solution

The fourth proportional to 678.85, 1,017.49 and 312.87 is: 468.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.85 : 1,017.49 = 312.87 : x
  2. Step 2: Convert to fraction form
    678.85/1,017.49 = 312.87/x
  3. Step 3: Cross multiply
    678.85x = 1,017.49 × 312.87
  4. Step 4: Simplify right side
    678.85x = 318,342.10
  5. Step 5: Solve for x
    x = 318,342.10/678.85
  6. Step 6: Final answer
    x = 468.94

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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.