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Finding the Fourth Proportional to 718.64, 991.55 and 419.80

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Solution

The fourth proportional to 718.64, 991.55 and 419.80 is: 579.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.64 : 991.55 = 419.80 : x
  2. Step 2: Convert to fraction form
    718.64/991.55 = 419.80/x
  3. Step 3: Cross multiply
    718.64x = 991.55 × 419.80
  4. Step 4: Simplify right side
    718.64x = 416,252.69
  5. Step 5: Solve for x
    x = 416,252.69/718.64
  6. Step 6: Final answer
    x = 579.22

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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.