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Finding the Fourth Proportional to 387.91, 535.17 and 289.50

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Solution

The fourth proportional to 387.91, 535.17 and 289.50 is: 399.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.91 : 535.17 = 289.50 : x
  2. Step 2: Convert to fraction form
    387.91/535.17 = 289.50/x
  3. Step 3: Cross multiply
    387.91x = 535.17 × 289.50
  4. Step 4: Simplify right side
    387.91x = 154,931.72
  5. Step 5: Solve for x
    x = 154,931.72/387.91
  6. Step 6: Final answer
    x = 399.40

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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.