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Finding the Fourth Proportional to 1,312.40, 1,810.55 and 840.19

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Solution

The fourth proportional to 1,312.40, 1,810.55 and 840.19 is: 1,159.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,312.40 : 1,810.55 = 840.19 : x
  2. Step 2: Convert to fraction form
    1,312.40/1,810.55 = 840.19/x
  3. Step 3: Cross multiply
    1,312.40x = 1,810.55 × 840.19
  4. Step 4: Simplify right side
    1,312.40x = 1,521,192.75
  5. Step 5: Solve for x
    x = 1,521,192.75/1,312.40
  6. Step 6: Final answer
    x = 1,159.10

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1.5x scale

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.