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Finding the Fourth Proportional to 1,285.88, 1,929.10 and 420.28

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Solution

The fourth proportional to 1,285.88, 1,929.10 and 420.28 is: 630.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.88 : 1,929.10 = 420.28 : x
  2. Step 2: Convert to fraction form
    1,285.88/1,929.10 = 420.28/x
  3. Step 3: Cross multiply
    1,285.88x = 1,929.10 × 420.28
  4. Step 4: Simplify right side
    1,285.88x = 810,762.15
  5. Step 5: Solve for x
    x = 810,762.15/1,285.88
  6. Step 6: Final answer
    x = 630.51

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1.5x scale

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.