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Finding the Fourth Proportional to 974.34, 1,345.13 and 643.55

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Solution

The fourth proportional to 974.34, 1,345.13 and 643.55 is: 888.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    974.34 : 1,345.13 = 643.55 : x
  2. Step 2: Convert to fraction form
    974.34/1,345.13 = 643.55/x
  3. Step 3: Cross multiply
    974.34x = 1,345.13 × 643.55
  4. Step 4: Simplify right side
    974.34x = 865,658.41
  5. Step 5: Solve for x
    x = 865,658.41/974.34
  6. Step 6: Final answer
    x = 888.46

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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.