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Finding the Fourth Proportional to 505.60, 698.40 and 491.20

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Solution

The fourth proportional to 505.60, 698.40 and 491.20 is: 678.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.60 : 698.40 = 491.20 : x
  2. Step 2: Convert to fraction form
    505.60/698.40 = 491.20/x
  3. Step 3: Cross multiply
    505.60x = 698.40 × 491.20
  4. Step 4: Simplify right side
    505.60x = 343,054.08
  5. Step 5: Solve for x
    x = 343,054.08/505.60
  6. Step 6: Final answer
    x = 678.51

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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.