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Finding the Fourth Proportional to 1,390.08, 2,085.12 and 478.08

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Solution

The fourth proportional to 1,390.08, 2,085.12 and 478.08 is: 717.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.08 : 2,085.12 = 478.08 : x
  2. Step 2: Convert to fraction form
    1,390.08/2,085.12 = 478.08/x
  3. Step 3: Cross multiply
    1,390.08x = 2,085.12 × 478.08
  4. Step 4: Simplify right side
    1,390.08x = 996,854.17
  5. Step 5: Solve for x
    x = 996,854.17/1,390.08
  6. Step 6: Final answer
    x = 717.12

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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.