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Finding the Fourth Proportional to 420.40, 627.26 and 417.72

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Solution

The fourth proportional to 420.40, 627.26 and 417.72 is: 623.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.40 : 627.26 = 417.72 : x
  2. Step 2: Convert to fraction form
    420.40/627.26 = 417.72/x
  3. Step 3: Cross multiply
    420.40x = 627.26 × 417.72
  4. Step 4: Simplify right side
    420.40x = 262,019.05
  5. Step 5: Solve for x
    x = 262,019.05/420.40
  6. Step 6: Final answer
    x = 623.26

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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.