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Finding the Fourth Proportional to 948.72, 1,422.96 and 428.40

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Solution

The fourth proportional to 948.72, 1,422.96 and 428.40 is: 642.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    948.72 : 1,422.96 = 428.40 : x
  2. Step 2: Convert to fraction form
    948.72/1,422.96 = 428.40/x
  3. Step 3: Cross multiply
    948.72x = 1,422.96 × 428.40
  4. Step 4: Simplify right side
    948.72x = 609,596.06
  5. Step 5: Solve for x
    x = 609,596.06/948.72
  6. Step 6: Final answer
    x = 642.55

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.