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Finding the Fourth Proportional to 920.16, 1,378.80 and 486.72

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Solution

The fourth proportional to 920.16, 1,378.80 and 486.72 is: 729.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.16 : 1,378.80 = 486.72 : x
  2. Step 2: Convert to fraction form
    920.16/1,378.80 = 486.72/x
  3. Step 3: Cross multiply
    920.16x = 1,378.80 × 486.72
  4. Step 4: Simplify right side
    920.16x = 671,089.54
  5. Step 5: Solve for x
    x = 671,089.54/920.16
  6. Step 6: Final answer
    x = 729.32

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.