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Finding the Fourth Proportional to 810.66, 1,117.95 and 645.42

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Solution

The fourth proportional to 810.66, 1,117.95 and 645.42 is: 890.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.66 : 1,117.95 = 645.42 : x
  2. Step 2: Convert to fraction form
    810.66/1,117.95 = 645.42/x
  3. Step 3: Cross multiply
    810.66x = 1,117.95 × 645.42
  4. Step 4: Simplify right side
    810.66x = 721,547.29
  5. Step 5: Solve for x
    x = 721,547.29/810.66
  6. Step 6: Final answer
    x = 890.07

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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.