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Finding the Fourth Proportional to 486.96, 670.32 and 421.20

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Solution

The fourth proportional to 486.96, 670.32 and 421.20 is: 579.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.96 : 670.32 = 421.20 : x
  2. Step 2: Convert to fraction form
    486.96/670.32 = 421.20/x
  3. Step 3: Cross multiply
    486.96x = 670.32 × 421.20
  4. Step 4: Simplify right side
    486.96x = 282,338.78
  5. Step 5: Solve for x
    x = 282,338.78/486.96
  6. Step 6: Final answer
    x = 579.80

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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.