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Finding the Fourth Proportional to 861.60, 1,189.20 and 665.52

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Solution

The fourth proportional to 861.60, 1,189.20 and 665.52 is: 918.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.60 : 1,189.20 = 665.52 : x
  2. Step 2: Convert to fraction form
    861.60/1,189.20 = 665.52/x
  3. Step 3: Cross multiply
    861.60x = 1,189.20 × 665.52
  4. Step 4: Simplify right side
    861.60x = 791,436.38
  5. Step 5: Solve for x
    x = 791,436.38/861.60
  6. Step 6: Final answer
    x = 918.57

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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.