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Finding the Fourth Proportional to 678.66, 1,018.12 and 313.82

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Solution

The fourth proportional to 678.66, 1,018.12 and 313.82 is: 470.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.66 : 1,018.12 = 313.82 : x
  2. Step 2: Convert to fraction form
    678.66/1,018.12 = 313.82/x
  3. Step 3: Cross multiply
    678.66x = 1,018.12 × 313.82
  4. Step 4: Simplify right side
    678.66x = 319,506.42
  5. Step 5: Solve for x
    x = 319,506.42/678.66
  6. Step 6: Final answer
    x = 470.79

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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.