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Finding the Fourth Proportional to 810, 1,117.90 and 478.71

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Solution

The fourth proportional to 810, 1,117.90 and 478.71 is: 660.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    810 : 1,117.90 = 478.71 : x
  2. Step 2: Convert to fraction form
    810/1,117.90 = 478.71/x
  3. Step 3: Cross multiply
    810x = 1,117.90 × 478.71
  4. Step 4: Simplify right side
    810x = 535,150.51
  5. Step 5: Solve for x
    x = 535,150.51/810
  6. Step 6: Final answer
    x = 660.68

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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.