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Finding the Fourth Proportional to 691.21, 953.40 and 428.77

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Solution

The fourth proportional to 691.21, 953.40 and 428.77 is: 591.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.21 : 953.40 = 428.77 : x
  2. Step 2: Convert to fraction form
    691.21/953.40 = 428.77/x
  3. Step 3: Cross multiply
    691.21x = 953.40 × 428.77
  4. Step 4: Simplify right side
    691.21x = 408,789.32
  5. Step 5: Solve for x
    x = 408,789.32/691.21
  6. Step 6: Final answer
    x = 591.41

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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.