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Finding the Fourth Proportional to 661.93, 991.18 and 642.45

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Solution

The fourth proportional to 661.93, 991.18 and 642.45 is: 962.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.93 : 991.18 = 642.45 : x
  2. Step 2: Convert to fraction form
    661.93/991.18 = 642.45/x
  3. Step 3: Cross multiply
    661.93x = 991.18 × 642.45
  4. Step 4: Simplify right side
    661.93x = 636,780.73
  5. Step 5: Solve for x
    x = 636,780.73/661.93
  6. Step 6: Final answer
    x = 962.01

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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.