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Finding the Fourth Proportional to 860, 1,186.80 and 492

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Solution

The fourth proportional to 860, 1,186.80 and 492 is: 678.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    860 : 1,186.80 = 492 : x
  2. Step 2: Convert to fraction form
    860/1,186.80 = 492/x
  3. Step 3: Cross multiply
    860x = 1,186.80 × 492
  4. Step 4: Simplify right side
    860x = 583,905.60
  5. Step 5: Solve for x
    x = 583,905.60/860
  6. Step 6: Final answer
    x = 678.96

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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.