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Finding the Fourth Proportional to 856.61, 1,284.95 and 387.99

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Solution

The fourth proportional to 856.61, 1,284.95 and 387.99 is: 582.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.61 : 1,284.95 = 387.99 : x
  2. Step 2: Convert to fraction form
    856.61/1,284.95 = 387.99/x
  3. Step 3: Cross multiply
    856.61x = 1,284.95 × 387.99
  4. Step 4: Simplify right side
    856.61x = 498,547.75
  5. Step 5: Solve for x
    x = 498,547.75/856.61
  6. Step 6: Final answer
    x = 582.00

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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.