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Finding the Fourth Proportional to 974.60, 1,345.50 and 642.90

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Solution

The fourth proportional to 974.60, 1,345.50 and 642.90 is: 887.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    974.60 : 1,345.50 = 642.90 : x
  2. Step 2: Convert to fraction form
    974.60/1,345.50 = 642.90/x
  3. Step 3: Cross multiply
    974.60x = 1,345.50 × 642.90
  4. Step 4: Simplify right side
    974.60x = 865,021.95
  5. Step 5: Solve for x
    x = 865,021.95/974.60
  6. Step 6: Final answer
    x = 887.57

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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.