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Finding the Fourth Proportional to 678.02, 1,017.09 and 312.75

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Solution

The fourth proportional to 678.02, 1,017.09 and 312.75 is: 469.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.02 : 1,017.09 = 312.75 : x
  2. Step 2: Convert to fraction form
    678.02/1,017.09 = 312.75/x
  3. Step 3: Cross multiply
    678.02x = 1,017.09 × 312.75
  4. Step 4: Simplify right side
    678.02x = 318,094.90
  5. Step 5: Solve for x
    x = 318,094.90/678.02
  6. Step 6: Final answer
    x = 469.15

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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.