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Finding the Fourth Proportional to 989.90, 1,365.60 and 570.18

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Solution

The fourth proportional to 989.90, 1,365.60 and 570.18 is: 786.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.90 : 1,365.60 = 570.18 : x
  2. Step 2: Convert to fraction form
    989.90/1,365.60 = 570.18/x
  3. Step 3: Cross multiply
    989.90x = 1,365.60 × 570.18
  4. Step 4: Simplify right side
    989.90x = 778,637.81
  5. Step 5: Solve for x
    x = 778,637.81/989.90
  6. Step 6: Final answer
    x = 786.58

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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.