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Finding the Fourth Proportional to 678.62, 1,017.14 and 312.63

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Solution

The fourth proportional to 678.62, 1,017.14 and 312.63 is: 468.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.62 : 1,017.14 = 312.63 : x
  2. Step 2: Convert to fraction form
    678.62/1,017.14 = 312.63/x
  3. Step 3: Cross multiply
    678.62x = 1,017.14 × 312.63
  4. Step 4: Simplify right side
    678.62x = 317,988.48
  5. Step 5: Solve for x
    x = 317,988.48/678.62
  6. Step 6: Final answer
    x = 468.58

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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.