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Finding the Fourth Proportional to 856.20, 1,281.10 and 779.40

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Solution

The fourth proportional to 856.20, 1,281.10 and 779.40 is: 1,166.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.20 : 1,281.10 = 779.40 : x
  2. Step 2: Convert to fraction form
    856.20/1,281.10 = 779.40/x
  3. Step 3: Cross multiply
    856.20x = 1,281.10 × 779.40
  4. Step 4: Simplify right side
    856.20x = 998,489.34
  5. Step 5: Solve for x
    x = 998,489.34/856.20
  6. Step 6: Final answer
    x = 1,166.19

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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.