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Finding the Fourth Proportional to 718.67, 989.39 and 644.86

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Solution

The fourth proportional to 718.67, 989.39 and 644.86 is: 887.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.67 : 989.39 = 644.86 : x
  2. Step 2: Convert to fraction form
    718.67/989.39 = 644.86/x
  3. Step 3: Cross multiply
    718.67x = 989.39 × 644.86
  4. Step 4: Simplify right side
    718.67x = 638,019.07
  5. Step 5: Solve for x
    x = 638,019.07/718.67
  6. Step 6: Final answer
    x = 887.77

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.