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Finding the Fourth Proportional to 715.45, 987.35 and 400.74

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Solution

The fourth proportional to 715.45, 987.35 and 400.74 is: 553.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.45 : 987.35 = 400.74 : x
  2. Step 2: Convert to fraction form
    715.45/987.35 = 400.74/x
  3. Step 3: Cross multiply
    715.45x = 987.35 × 400.74
  4. Step 4: Simplify right side
    715.45x = 395,670.64
  5. Step 5: Solve for x
    x = 395,670.64/715.45
  6. Step 6: Final answer
    x = 553.04

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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.