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Finding the Fourth Proportional to 420.89, 631.12 and 266.70

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Solution

The fourth proportional to 420.89, 631.12 and 266.70 is: 399.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.89 : 631.12 = 266.70 : x
  2. Step 2: Convert to fraction form
    420.89/631.12 = 266.70/x
  3. Step 3: Cross multiply
    420.89x = 631.12 × 266.70
  4. Step 4: Simplify right side
    420.89x = 168,317.34
  5. Step 5: Solve for x
    x = 168,317.34/420.89
  6. Step 6: Final answer
    x = 399.91

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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.