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Finding the Fourth Proportional to 660.76, 986.15 and 643.48

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Solution

The fourth proportional to 660.76, 986.15 and 643.48 is: 960.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.76 : 986.15 = 643.48 : x
  2. Step 2: Convert to fraction form
    660.76/986.15 = 643.48/x
  3. Step 3: Cross multiply
    660.76x = 986.15 × 643.48
  4. Step 4: Simplify right side
    660.76x = 634,567.80
  5. Step 5: Solve for x
    x = 634,567.80/660.76
  6. Step 6: Final answer
    x = 960.36

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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.