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Finding the Fourth Proportional to 860.68, 1,187.78 and 511.40

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Solution

The fourth proportional to 860.68, 1,187.78 and 511.40 is: 705.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.68 : 1,187.78 = 511.40 : x
  2. Step 2: Convert to fraction form
    860.68/1,187.78 = 511.40/x
  3. Step 3: Cross multiply
    860.68x = 1,187.78 × 511.40
  4. Step 4: Simplify right side
    860.68x = 607,430.69
  5. Step 5: Solve for x
    x = 607,430.69/860.68
  6. Step 6: Final answer
    x = 705.76

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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.