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Finding the Fourth Proportional to 991.88, 1,487.82 and 645.50

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Solution

The fourth proportional to 991.88, 1,487.82 and 645.50 is: 968.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.88 : 1,487.82 = 645.50 : x
  2. Step 2: Convert to fraction form
    991.88/1,487.82 = 645.50/x
  3. Step 3: Cross multiply
    991.88x = 1,487.82 × 645.50
  4. Step 4: Simplify right side
    991.88x = 960,387.81
  5. Step 5: Solve for x
    x = 960,387.81/991.88
  6. Step 6: Final answer
    x = 968.25

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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.