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Finding the Fourth Proportional to 669.64, 924.30 and 390

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Solution

The fourth proportional to 669.64, 924.30 and 390 is: 538.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.64 : 924.30 = 390 : x
  2. Step 2: Convert to fraction form
    669.64/924.30 = 390/x
  3. Step 3: Cross multiply
    669.64x = 924.30 × 390
  4. Step 4: Simplify right side
    669.64x = 360,477
  5. Step 5: Solve for x
    x = 360,477/669.64
  6. Step 6: Final answer
    x = 538.31

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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.