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Finding the Fourth Proportional to 1,128, 1,690.08 and 478.40

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Solution

The fourth proportional to 1,128, 1,690.08 and 478.40 is: 716.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128 : 1,690.08 = 478.40 : x
  2. Step 2: Convert to fraction form
    1,128/1,690.08 = 478.40/x
  3. Step 3: Cross multiply
    1,128x = 1,690.08 × 478.40
  4. Step 4: Simplify right side
    1,128x = 808,534.27
  5. Step 5: Solve for x
    x = 808,534.27/1,128
  6. Step 6: Final answer
    x = 716.79

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.