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Finding the Fourth Proportional to 642.42, 885.78 and 455.58

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Solution

The fourth proportional to 642.42, 885.78 and 455.58 is: 628.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.42 : 885.78 = 455.58 : x
  2. Step 2: Convert to fraction form
    642.42/885.78 = 455.58/x
  3. Step 3: Cross multiply
    642.42x = 885.78 × 455.58
  4. Step 4: Simplify right side
    642.42x = 403,543.65
  5. Step 5: Solve for x
    x = 403,543.65/642.42
  6. Step 6: Final answer
    x = 628.16

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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.