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Finding the Fourth Proportional to 678.24, 1,017.28 and 312.93

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Solution

The fourth proportional to 678.24, 1,017.28 and 312.93 is: 469.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.24 : 1,017.28 = 312.93 : x
  2. Step 2: Convert to fraction form
    678.24/1,017.28 = 312.93/x
  3. Step 3: Cross multiply
    678.24x = 1,017.28 × 312.93
  4. Step 4: Simplify right side
    678.24x = 318,337.43
  5. Step 5: Solve for x
    x = 318,337.43/678.24
  6. Step 6: Final answer
    x = 469.36

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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.