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Finding the Fourth Proportional to 623.12, 860.16 and 390.40

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Solution

The fourth proportional to 623.12, 860.16 and 390.40 is: 538.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    623.12 : 860.16 = 390.40 : x
  2. Step 2: Convert to fraction form
    623.12/860.16 = 390.40/x
  3. Step 3: Cross multiply
    623.12x = 860.16 × 390.40
  4. Step 4: Simplify right side
    623.12x = 335,806.46
  5. Step 5: Solve for x
    x = 335,806.46/623.12
  6. Step 6: Final answer
    x = 538.91

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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.