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Finding the Fourth Proportional to 612.78, 919.17 and 430.99

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Solution

The fourth proportional to 612.78, 919.17 and 430.99 is: 646.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.78 : 919.17 = 430.99 : x
  2. Step 2: Convert to fraction form
    612.78/919.17 = 430.99/x
  3. Step 3: Cross multiply
    612.78x = 919.17 × 430.99
  4. Step 4: Simplify right side
    612.78x = 396,150.78
  5. Step 5: Solve for x
    x = 396,150.78/612.78
  6. Step 6: Final answer
    x = 646.48

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Double scale
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Similar ratio
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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.