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Finding the Fourth Proportional to 972.96, 1,342.88 and 641.40

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Solution

The fourth proportional to 972.96, 1,342.88 and 641.40 is: 885.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    972.96 : 1,342.88 = 641.40 : x
  2. Step 2: Convert to fraction form
    972.96/1,342.88 = 641.40/x
  3. Step 3: Cross multiply
    972.96x = 1,342.88 × 641.40
  4. Step 4: Simplify right side
    972.96x = 861,323.23
  5. Step 5: Solve for x
    x = 861,323.23/972.96
  6. Step 6: Final answer
    x = 885.26

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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.