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Finding the Fourth Proportional to 1,159.50, 1,739.25 and 390

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Solution

The fourth proportional to 1,159.50, 1,739.25 and 390 is: 585

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,159.50 : 1,739.25 = 390 : x
  2. Step 2: Convert to fraction form
    1,159.50/1,739.25 = 390/x
  3. Step 3: Cross multiply
    1,159.50x = 1,739.25 × 390
  4. Step 4: Simplify right side
    1,159.50x = 678,307.50
  5. Step 5: Solve for x
    x = 678,307.50/1,159.50
  6. Step 6: Final answer
    x = 585

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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.