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Finding the Fourth Proportional to 390.30, 584.88 and 287.76

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Solution

The fourth proportional to 390.30, 584.88 and 287.76 is: 431.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.30 : 584.88 = 287.76 : x
  2. Step 2: Convert to fraction form
    390.30/584.88 = 287.76/x
  3. Step 3: Cross multiply
    390.30x = 584.88 × 287.76
  4. Step 4: Simplify right side
    390.30x = 168,305.07
  5. Step 5: Solve for x
    x = 168,305.07/390.30
  6. Step 6: Final answer
    x = 431.22

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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.