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Finding the Fourth Proportional to 387.90, 581.88 and 285

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Solution

The fourth proportional to 387.90, 581.88 and 285 is: 427.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.90 : 581.88 = 285 : x
  2. Step 2: Convert to fraction form
    387.90/581.88 = 285/x
  3. Step 3: Cross multiply
    387.90x = 581.88 × 285
  4. Step 4: Simplify right side
    387.90x = 165,835.80
  5. Step 5: Solve for x
    x = 165,835.80/387.90
  6. Step 6: Final answer
    x = 427.52

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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.