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Finding the Fourth Proportional to 718.80, 991.80 and 497.40

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Solution

The fourth proportional to 718.80, 991.80 and 497.40 is: 686.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.80 : 991.80 = 497.40 : x
  2. Step 2: Convert to fraction form
    718.80/991.80 = 497.40/x
  3. Step 3: Cross multiply
    718.80x = 991.80 × 497.40
  4. Step 4: Simplify right side
    718.80x = 493,321.32
  5. Step 5: Solve for x
    x = 493,321.32/718.80
  6. Step 6: Final answer
    x = 686.31

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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.