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Finding the Fourth Proportional to 587.58, 810.78 and 390.78

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Solution

The fourth proportional to 587.58, 810.78 and 390.78 is: 539.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    587.58 : 810.78 = 390.78 : x
  2. Step 2: Convert to fraction form
    587.58/810.78 = 390.78/x
  3. Step 3: Cross multiply
    587.58x = 810.78 × 390.78
  4. Step 4: Simplify right side
    587.58x = 316,836.61
  5. Step 5: Solve for x
    x = 316,836.61/587.58
  6. Step 6: Final answer
    x = 539.22

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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.