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Finding the Fourth Proportional to 399.78, 596.16 and 390.06

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Solution

The fourth proportional to 399.78, 596.16 and 390.06 is: 581.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.78 : 596.16 = 390.06 : x
  2. Step 2: Convert to fraction form
    399.78/596.16 = 390.06/x
  3. Step 3: Cross multiply
    399.78x = 596.16 × 390.06
  4. Step 4: Simplify right side
    399.78x = 232,538.17
  5. Step 5: Solve for x
    x = 232,538.17/399.78
  6. Step 6: Final answer
    x = 581.67

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.