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Finding the Fourth Proportional to 666.14, 991.88 and 642.76

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Solution

The fourth proportional to 666.14, 991.88 and 642.76 is: 957.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.14 : 991.88 = 642.76 : x
  2. Step 2: Convert to fraction form
    666.14/991.88 = 642.76/x
  3. Step 3: Cross multiply
    666.14x = 991.88 × 642.76
  4. Step 4: Simplify right side
    666.14x = 637,540.79
  5. Step 5: Solve for x
    x = 637,540.79/666.14
  6. Step 6: Final answer
    x = 957.07

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.