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Finding the Fourth Proportional to 712.89, 977.51 and 642.66

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Solution

The fourth proportional to 712.89, 977.51 and 642.66 is: 881.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.89 : 977.51 = 642.66 : x
  2. Step 2: Convert to fraction form
    712.89/977.51 = 642.66/x
  3. Step 3: Cross multiply
    712.89x = 977.51 × 642.66
  4. Step 4: Simplify right side
    712.89x = 628,203.36
  5. Step 5: Solve for x
    x = 628,203.36/712.89
  6. Step 6: Final answer
    x = 881.21

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.