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Finding the Fourth Proportional to 390.40, 582.40 and 390.40

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Solution

The fourth proportional to 390.40, 582.40 and 390.40 is: 582.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.40 : 582.40 = 390.40 : x
  2. Step 2: Convert to fraction form
    390.40/582.40 = 390.40/x
  3. Step 3: Cross multiply
    390.40x = 582.40 × 390.40
  4. Step 4: Simplify right side
    390.40x = 227,368.96
  5. Step 5: Solve for x
    x = 227,368.96/390.40
  6. Step 6: Final answer
    x = 582.40

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.