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Finding the Fourth Proportional to 663.90, 916.20 and 380.32

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Solution

The fourth proportional to 663.90, 916.20 and 380.32 is: 524.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.90 : 916.20 = 380.32 : x
  2. Step 2: Convert to fraction form
    663.90/916.20 = 380.32/x
  3. Step 3: Cross multiply
    663.90x = 916.20 × 380.32
  4. Step 4: Simplify right side
    663.90x = 348,449.18
  5. Step 5: Solve for x
    x = 348,449.18/663.90
  6. Step 6: Final answer
    x = 524.85

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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.