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Finding the Fourth Proportional to 686.68, 947.69 and 665.15

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Solution

The fourth proportional to 686.68, 947.69 and 665.15 is: 917.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.68 : 947.69 = 665.15 : x
  2. Step 2: Convert to fraction form
    686.68/947.69 = 665.15/x
  3. Step 3: Cross multiply
    686.68x = 947.69 × 665.15
  4. Step 4: Simplify right side
    686.68x = 630,354.18
  5. Step 5: Solve for x
    x = 630,354.18/686.68
  6. Step 6: Final answer
    x = 917.98

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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.