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Finding the Fourth Proportional to 678.02, 1,017.07 and 215.78

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Solution

The fourth proportional to 678.02, 1,017.07 and 215.78 is: 323.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.02 : 1,017.07 = 215.78 : x
  2. Step 2: Convert to fraction form
    678.02/1,017.07 = 215.78/x
  3. Step 3: Cross multiply
    678.02x = 1,017.07 × 215.78
  4. Step 4: Simplify right side
    678.02x = 219,457.74
  5. Step 5: Solve for x
    x = 219,457.74/678.02
  6. Step 6: Final answer
    x = 323.68

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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.