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Finding the Fourth Proportional to 747.40, 1,030.80 and 485.68

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Solution

The fourth proportional to 747.40, 1,030.80 and 485.68 is: 669.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    747.40 : 1,030.80 = 485.68 : x
  2. Step 2: Convert to fraction form
    747.40/1,030.80 = 485.68/x
  3. Step 3: Cross multiply
    747.40x = 1,030.80 × 485.68
  4. Step 4: Simplify right side
    747.40x = 500,638.94
  5. Step 5: Solve for x
    x = 500,638.94/747.40
  6. Step 6: Final answer
    x = 669.84

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1.5x scale

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.