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Finding the Fourth Proportional to 415.80, 623.70 and 221.40

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Solution

The fourth proportional to 415.80, 623.70 and 221.40 is: 332.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.80 : 623.70 = 221.40 : x
  2. Step 2: Convert to fraction form
    415.80/623.70 = 221.40/x
  3. Step 3: Cross multiply
    415.80x = 623.70 × 221.40
  4. Step 4: Simplify right side
    415.80x = 138,087.18
  5. Step 5: Solve for x
    x = 138,087.18/415.80
  6. Step 6: Final answer
    x = 332.10

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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.