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Finding the Fourth Proportional to 856.74, 1,284.75 and 394.38

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Solution

The fourth proportional to 856.74, 1,284.75 and 394.38 is: 591.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.74 : 1,284.75 = 394.38 : x
  2. Step 2: Convert to fraction form
    856.74/1,284.75 = 394.38/x
  3. Step 3: Cross multiply
    856.74x = 1,284.75 × 394.38
  4. Step 4: Simplify right side
    856.74x = 506,679.71
  5. Step 5: Solve for x
    x = 506,679.71/856.74
  6. Step 6: Final answer
    x = 591.40

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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.