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Finding the Fourth Proportional to 421.10, 581.40 and 310.80

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Solution

The fourth proportional to 421.10, 581.40 and 310.80 is: 429.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.10 : 581.40 = 310.80 : x
  2. Step 2: Convert to fraction form
    421.10/581.40 = 310.80/x
  3. Step 3: Cross multiply
    421.10x = 581.40 × 310.80
  4. Step 4: Simplify right side
    421.10x = 180,699.12
  5. Step 5: Solve for x
    x = 180,699.12/421.10
  6. Step 6: Final answer
    x = 429.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.