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Finding the Fourth Proportional to 921.05, 1,271.18 and 528.20

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Solution

The fourth proportional to 921.05, 1,271.18 and 528.20 is: 728.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.05 : 1,271.18 = 528.20 : x
  2. Step 2: Convert to fraction form
    921.05/1,271.18 = 528.20/x
  3. Step 3: Cross multiply
    921.05x = 1,271.18 × 528.20
  4. Step 4: Simplify right side
    921.05x = 671,432.24
  5. Step 5: Solve for x
    x = 671,432.24/921.05
  6. Step 6: Final answer
    x = 728.99

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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.