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Finding the Fourth Proportional to 921.40, 1,271.58 and 528.55

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Solution

The fourth proportional to 921.40, 1,271.58 and 528.55 is: 729.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.40 : 1,271.58 = 528.55 : x
  2. Step 2: Convert to fraction form
    921.40/1,271.58 = 528.55/x
  3. Step 3: Cross multiply
    921.40x = 1,271.58 × 528.55
  4. Step 4: Simplify right side
    921.40x = 672,093.61
  5. Step 5: Solve for x
    x = 672,093.61/921.40
  6. Step 6: Final answer
    x = 729.43

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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.