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Finding the Fourth Proportional to 421.35, 581.54 and 311.40

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Solution

The fourth proportional to 421.35, 581.54 and 311.40 is: 429.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.35 : 581.54 = 311.40 : x
  2. Step 2: Convert to fraction form
    421.35/581.54 = 311.40/x
  3. Step 3: Cross multiply
    421.35x = 581.54 × 311.40
  4. Step 4: Simplify right side
    421.35x = 181,090.00
  5. Step 5: Solve for x
    x = 181,090.00/421.35
  6. Step 6: Final answer
    x = 429.79

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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.