Home / 140.28-210.70-85.51

Finding the Fourth Proportional to 140.28, 210.70 and 85.51

Calculator

Solution

The fourth proportional to 140.28, 210.70 and 85.51 is: 128.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.28 : 210.70 = 85.51 : x
  2. Step 2: Convert to fraction form
    140.28/210.70 = 85.51/x
  3. Step 3: Cross multiply
    140.28x = 210.70 × 85.51
  4. Step 4: Simplify right side
    140.28x = 18,016.14
  5. Step 5: Solve for x
    x = 18,016.14/140.28
  6. Step 6: Final answer
    x = 128.43

Related Problems

Find fourth proportional to 70.14, 105.35 and 42.75
Half scale
Find fourth proportional to 280.56, 421.40 and 171.01
Double scale
Find fourth proportional to 141.28, 212.20 and 86.51
Similar ratio
Find fourth proportional to 210.42, 316.05 and 128.26
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.