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Finding the Fourth Proportional to 929.52, 1,278.72 and 781.20

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Solution

The fourth proportional to 929.52, 1,278.72 and 781.20 is: 1,074.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    929.52 : 1,278.72 = 781.20 : x
  2. Step 2: Convert to fraction form
    929.52/1,278.72 = 781.20/x
  3. Step 3: Cross multiply
    929.52x = 1,278.72 × 781.20
  4. Step 4: Simplify right side
    929.52x = 998,936.06
  5. Step 5: Solve for x
    x = 998,936.06/929.52
  6. Step 6: Final answer
    x = 1,074.68

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1.5x scale

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.