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Finding the Fourth Proportional to 905.76, 1,248.84 and 643.32

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Solution

The fourth proportional to 905.76, 1,248.84 and 643.32 is: 886.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.76 : 1,248.84 = 643.32 : x
  2. Step 2: Convert to fraction form
    905.76/1,248.84 = 643.32/x
  3. Step 3: Cross multiply
    905.76x = 1,248.84 × 643.32
  4. Step 4: Simplify right side
    905.76x = 803,403.75
  5. Step 5: Solve for x
    x = 803,403.75/905.76
  6. Step 6: Final answer
    x = 886.99

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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.