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Finding the Fourth Proportional to 58.40, 87.60 and 43.20

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Solution

The fourth proportional to 58.40, 87.60 and 43.20 is: 64.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    58.40 : 87.60 = 43.20 : x
  2. Step 2: Convert to fraction form
    58.40/87.60 = 43.20/x
  3. Step 3: Cross multiply
    58.40x = 87.60 × 43.20
  4. Step 4: Simplify right side
    58.40x = 3,784.32
  5. Step 5: Solve for x
    x = 3,784.32/58.40
  6. Step 6: Final answer
    x = 64.80

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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.