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Finding the Fourth Proportional to 991.86, 1,487.40 and 471.78

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Solution

The fourth proportional to 991.86, 1,487.40 and 471.78 is: 707.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.86 : 1,487.40 = 471.78 : x
  2. Step 2: Convert to fraction form
    991.86/1,487.40 = 471.78/x
  3. Step 3: Cross multiply
    991.86x = 1,487.40 × 471.78
  4. Step 4: Simplify right side
    991.86x = 701,725.57
  5. Step 5: Solve for x
    x = 701,725.57/991.86
  6. Step 6: Final answer
    x = 707.48

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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.