Home / 801.20-1,201.80-787.70

Finding the Fourth Proportional to 801.20, 1,201.80 and 787.70

Calculator

Solution

The fourth proportional to 801.20, 1,201.80 and 787.70 is: 1,181.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    801.20 : 1,201.80 = 787.70 : x
  2. Step 2: Convert to fraction form
    801.20/1,201.80 = 787.70/x
  3. Step 3: Cross multiply
    801.20x = 1,201.80 × 787.70
  4. Step 4: Simplify right side
    801.20x = 946,657.86
  5. Step 5: Solve for x
    x = 946,657.86/801.20
  6. Step 6: Final answer
    x = 1,181.55

Related Problems

Find fourth proportional to 400.60, 600.90 and 393.85
Half scale
Find fourth proportional to 1,602.40, 2,403.60 and 1,575.40
Double scale
Find fourth proportional to 802.20, 1,203.30 and 788.70
Similar ratio
Find fourth proportional to 1,201.80, 1,802.70 and 1,181.55
1.5x scale

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.