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Finding the Fourth Proportional to 712.78, 983.65 and 398.09

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Solution

The fourth proportional to 712.78, 983.65 and 398.09 is: 549.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.78 : 983.65 = 398.09 : x
  2. Step 2: Convert to fraction form
    712.78/983.65 = 398.09/x
  3. Step 3: Cross multiply
    712.78x = 983.65 × 398.09
  4. Step 4: Simplify right side
    712.78x = 391,581.23
  5. Step 5: Solve for x
    x = 391,581.23/712.78
  6. Step 6: Final answer
    x = 549.38

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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.