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Finding the Fourth Proportional to 974.32, 1,345.12 and 643.71

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Solution

The fourth proportional to 974.32, 1,345.12 and 643.71 is: 888.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    974.32 : 1,345.12 = 643.71 : x
  2. Step 2: Convert to fraction form
    974.32/1,345.12 = 643.71/x
  3. Step 3: Cross multiply
    974.32x = 1,345.12 × 643.71
  4. Step 4: Simplify right side
    974.32x = 865,860.54
  5. Step 5: Solve for x
    x = 865,860.54/974.32
  6. Step 6: Final answer
    x = 888.68

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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.