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Finding the Fourth Proportional to 931.39, 1,285.35 and 511.78

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Solution

The fourth proportional to 931.39, 1,285.35 and 511.78 is: 706.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    931.39 : 1,285.35 = 511.78 : x
  2. Step 2: Convert to fraction form
    931.39/1,285.35 = 511.78/x
  3. Step 3: Cross multiply
    931.39x = 1,285.35 × 511.78
  4. Step 4: Simplify right side
    931.39x = 657,816.42
  5. Step 5: Solve for x
    x = 657,816.42/931.39
  6. Step 6: Final answer
    x = 706.27

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Double scale
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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.