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Finding the Fourth Proportional to 856.40, 1,283.47 and 387.52

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Solution

The fourth proportional to 856.40, 1,283.47 and 387.52 is: 580.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.40 : 1,283.47 = 387.52 : x
  2. Step 2: Convert to fraction form
    856.40/1,283.47 = 387.52/x
  3. Step 3: Cross multiply
    856.40x = 1,283.47 × 387.52
  4. Step 4: Simplify right side
    856.40x = 497,366.12
  5. Step 5: Solve for x
    x = 497,366.12/856.40
  6. Step 6: Final answer
    x = 580.77

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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.