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Finding the Fourth Proportional to 642.38, 886.86 and 486.86

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Solution

The fourth proportional to 642.38, 886.86 and 486.86 is: 672.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.38 : 886.86 = 486.86 : x
  2. Step 2: Convert to fraction form
    642.38/886.86 = 486.86/x
  3. Step 3: Cross multiply
    642.38x = 886.86 × 486.86
  4. Step 4: Simplify right side
    642.38x = 431,772.23
  5. Step 5: Solve for x
    x = 431,772.23/642.38
  6. Step 6: Final answer
    x = 672.15

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1.5x scale

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.