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Finding the Fourth Proportional to 663.86, 989.95 and 617.69

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Solution

The fourth proportional to 663.86, 989.95 and 617.69 is: 921.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.86 : 989.95 = 617.69 : x
  2. Step 2: Convert to fraction form
    663.86/989.95 = 617.69/x
  3. Step 3: Cross multiply
    663.86x = 989.95 × 617.69
  4. Step 4: Simplify right side
    663.86x = 611,479.13
  5. Step 5: Solve for x
    x = 611,479.13/663.86
  6. Step 6: Final answer
    x = 921.10

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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.