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Finding the Fourth Proportional to 420.11, 630.45 and 290.40

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Solution

The fourth proportional to 420.11, 630.45 and 290.40 is: 435.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.11 : 630.45 = 290.40 : x
  2. Step 2: Convert to fraction form
    420.11/630.45 = 290.40/x
  3. Step 3: Cross multiply
    420.11x = 630.45 × 290.40
  4. Step 4: Simplify right side
    420.11x = 183,082.68
  5. Step 5: Solve for x
    x = 183,082.68/420.11
  6. Step 6: Final answer
    x = 435.80

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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.