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Finding the Fourth Proportional to 678.98, 1,018.60 and 216.72

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Solution

The fourth proportional to 678.98, 1,018.60 and 216.72 is: 325.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.98 : 1,018.60 = 216.72 : x
  2. Step 2: Convert to fraction form
    678.98/1,018.60 = 216.72/x
  3. Step 3: Cross multiply
    678.98x = 1,018.60 × 216.72
  4. Step 4: Simplify right side
    678.98x = 220,748.19
  5. Step 5: Solve for x
    x = 220,748.19/678.98
  6. Step 6: Final answer
    x = 325.12

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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.