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Finding the Fourth Proportional to 565.40, 780.40 and 388.72

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Solution

The fourth proportional to 565.40, 780.40 and 388.72 is: 536.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    565.40 : 780.40 = 388.72 : x
  2. Step 2: Convert to fraction form
    565.40/780.40 = 388.72/x
  3. Step 3: Cross multiply
    565.40x = 780.40 × 388.72
  4. Step 4: Simplify right side
    565.40x = 303,357.09
  5. Step 5: Solve for x
    x = 303,357.09/565.40
  6. Step 6: Final answer
    x = 536.54

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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.