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Finding the Fourth Proportional to 977.76, 1,349.12 and 628.40

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Solution

The fourth proportional to 977.76, 1,349.12 and 628.40 is: 867.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    977.76 : 1,349.12 = 628.40 : x
  2. Step 2: Convert to fraction form
    977.76/1,349.12 = 628.40/x
  3. Step 3: Cross multiply
    977.76x = 1,349.12 × 628.40
  4. Step 4: Simplify right side
    977.76x = 847,787.01
  5. Step 5: Solve for x
    x = 847,787.01/977.76
  6. Step 6: Final answer
    x = 867.07

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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.