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Finding the Fourth Proportional to 977.20, 1,347.51 and 645.20

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Solution

The fourth proportional to 977.20, 1,347.51 and 645.20 is: 889.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    977.20 : 1,347.51 = 645.20 : x
  2. Step 2: Convert to fraction form
    977.20/1,347.51 = 645.20/x
  3. Step 3: Cross multiply
    977.20x = 1,347.51 × 645.20
  4. Step 4: Simplify right side
    977.20x = 869,413.45
  5. Step 5: Solve for x
    x = 869,413.45/977.20
  6. Step 6: Final answer
    x = 889.70

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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.