Home / 143.78-215.75-66.78

Finding the Fourth Proportional to 143.78, 215.75 and 66.78

Calculator

Solution

The fourth proportional to 143.78, 215.75 and 66.78 is: 100.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.78 : 215.75 = 66.78 : x
  2. Step 2: Convert to fraction form
    143.78/215.75 = 66.78/x
  3. Step 3: Cross multiply
    143.78x = 215.75 × 66.78
  4. Step 4: Simplify right side
    143.78x = 14,407.95
  5. Step 5: Solve for x
    x = 14,407.95/143.78
  6. Step 6: Final answer
    x = 100.21

Related Problems

Find fourth proportional to 71.89, 107.88 and 33.39
Half scale
Find fourth proportional to 287.55, 431.51 and 133.56
Double scale
Find fourth proportional to 144.78, 217.25 and 67.78
Similar ratio
Find fourth proportional to 215.66, 323.63 and 100.17
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.