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Finding the Fourth Proportional to 890.78, 1,229.20 and 497.72

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Solution

The fourth proportional to 890.78, 1,229.20 and 497.72 is: 686.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.78 : 1,229.20 = 497.72 : x
  2. Step 2: Convert to fraction form
    890.78/1,229.20 = 497.72/x
  3. Step 3: Cross multiply
    890.78x = 1,229.20 × 497.72
  4. Step 4: Simplify right side
    890.78x = 611,799.25
  5. Step 5: Solve for x
    x = 611,799.25/890.78
  6. Step 6: Final answer
    x = 686.82

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Double scale
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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.