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Finding the Fourth Proportional to 486.78, 670.23 and 421.98

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Solution

The fourth proportional to 486.78, 670.23 and 421.98 is: 581.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.78 : 670.23 = 421.98 : x
  2. Step 2: Convert to fraction form
    486.78/670.23 = 421.98/x
  3. Step 3: Cross multiply
    486.78x = 670.23 × 421.98
  4. Step 4: Simplify right side
    486.78x = 282,823.66
  5. Step 5: Solve for x
    x = 282,823.66/486.78
  6. Step 6: Final answer
    x = 581.01

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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.