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Finding the Fourth Proportional to 686.23, 947.18 and 420.76

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Solution

The fourth proportional to 686.23, 947.18 and 420.76 is: 580.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.23 : 947.18 = 420.76 : x
  2. Step 2: Convert to fraction form
    686.23/947.18 = 420.76/x
  3. Step 3: Cross multiply
    686.23x = 947.18 × 420.76
  4. Step 4: Simplify right side
    686.23x = 398,535.46
  5. Step 5: Solve for x
    x = 398,535.46/686.23
  6. Step 6: Final answer
    x = 580.76

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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.