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Finding the Fourth Proportional to 430.16, 639.76 and 417.20

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Solution

The fourth proportional to 430.16, 639.76 and 417.20 is: 620.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.16 : 639.76 = 417.20 : x
  2. Step 2: Convert to fraction form
    430.16/639.76 = 417.20/x
  3. Step 3: Cross multiply
    430.16x = 639.76 × 417.20
  4. Step 4: Simplify right side
    430.16x = 266,907.87
  5. Step 5: Solve for x
    x = 266,907.87/430.16
  6. Step 6: Final answer
    x = 620.49

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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.