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Finding the Fourth Proportional to 421.48, 627.65 and 411.40

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Solution

The fourth proportional to 421.48, 627.65 and 411.40 is: 612.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.48 : 627.65 = 411.40 : x
  2. Step 2: Convert to fraction form
    421.48/627.65 = 411.40/x
  3. Step 3: Cross multiply
    421.48x = 627.65 × 411.40
  4. Step 4: Simplify right side
    421.48x = 258,215.21
  5. Step 5: Solve for x
    x = 258,215.21/421.48
  6. Step 6: Final answer
    x = 612.64

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.