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Finding the Fourth Proportional to 718.90, 991.94 and 497.78

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Solution

The fourth proportional to 718.90, 991.94 and 497.78 is: 686.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.90 : 991.94 = 497.78 : x
  2. Step 2: Convert to fraction form
    718.90/991.94 = 497.78/x
  3. Step 3: Cross multiply
    718.90x = 991.94 × 497.78
  4. Step 4: Simplify right side
    718.90x = 493,767.89
  5. Step 5: Solve for x
    x = 493,767.89/718.90
  6. Step 6: Final answer
    x = 686.84

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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.