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Finding the Fourth Proportional to 870.40, 1,200.78 and 538.60

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Solution

The fourth proportional to 870.40, 1,200.78 and 538.60 is: 743.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.40 : 1,200.78 = 538.60 : x
  2. Step 2: Convert to fraction form
    870.40/1,200.78 = 538.60/x
  3. Step 3: Cross multiply
    870.40x = 1,200.78 × 538.60
  4. Step 4: Simplify right side
    870.40x = 646,740.11
  5. Step 5: Solve for x
    x = 646,740.11/870.40
  6. Step 6: Final answer
    x = 743.04

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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.