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Finding the Fourth Proportional to 390.98, 586.48 and 218.75

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Solution

The fourth proportional to 390.98, 586.48 and 218.75 is: 328.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.98 : 586.48 = 218.75 : x
  2. Step 2: Convert to fraction form
    390.98/586.48 = 218.75/x
  3. Step 3: Cross multiply
    390.98x = 586.48 × 218.75
  4. Step 4: Simplify right side
    390.98x = 128,292.04
  5. Step 5: Solve for x
    x = 128,292.04/390.98
  6. Step 6: Final answer
    x = 328.13

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.