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Finding the Fourth Proportional to 663.90, 916.19 and 398.22

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Solution

The fourth proportional to 663.90, 916.19 and 398.22 is: 549.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.90 : 916.19 = 398.22 : x
  2. Step 2: Convert to fraction form
    663.90/916.19 = 398.22/x
  3. Step 3: Cross multiply
    663.90x = 916.19 × 398.22
  4. Step 4: Simplify right side
    663.90x = 364,845.18
  5. Step 5: Solve for x
    x = 364,845.18/663.90
  6. Step 6: Final answer
    x = 549.55

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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.