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Finding the Fourth Proportional to 420.96, 581.20 and 317.60

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Solution

The fourth proportional to 420.96, 581.20 and 317.60 is: 438.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.96 : 581.20 = 317.60 : x
  2. Step 2: Convert to fraction form
    420.96/581.20 = 317.60/x
  3. Step 3: Cross multiply
    420.96x = 581.20 × 317.60
  4. Step 4: Simplify right side
    420.96x = 184,589.12
  5. Step 5: Solve for x
    x = 184,589.12/420.96
  6. Step 6: Final answer
    x = 438.50

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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.