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Finding the Fourth Proportional to 1,438.80, 1,985.64 and 916.08

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Solution

The fourth proportional to 1,438.80, 1,985.64 and 916.08 is: 1,264.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,438.80 : 1,985.64 = 916.08 : x
  2. Step 2: Convert to fraction form
    1,438.80/1,985.64 = 916.08/x
  3. Step 3: Cross multiply
    1,438.80x = 1,985.64 × 916.08
  4. Step 4: Simplify right side
    1,438.80x = 1,819,005.09
  5. Step 5: Solve for x
    x = 1,819,005.09/1,438.80
  6. Step 6: Final answer
    x = 1,264.25

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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.