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Finding the Fourth Proportional to 430.42, 644.40 and 386.68

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Solution

The fourth proportional to 430.42, 644.40 and 386.68 is: 578.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.42 : 644.40 = 386.68 : x
  2. Step 2: Convert to fraction form
    430.42/644.40 = 386.68/x
  3. Step 3: Cross multiply
    430.42x = 644.40 × 386.68
  4. Step 4: Simplify right side
    430.42x = 249,176.59
  5. Step 5: Solve for x
    x = 249,176.59/430.42
  6. Step 6: Final answer
    x = 578.91

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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.