Home / 69.21-103.15-66.20

Finding the Fourth Proportional to 69.21, 103.15 and 66.20

Calculator

Solution

The fourth proportional to 69.21, 103.15 and 66.20 is: 98.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.21 : 103.15 = 66.20 : x
  2. Step 2: Convert to fraction form
    69.21/103.15 = 66.20/x
  3. Step 3: Cross multiply
    69.21x = 103.15 × 66.20
  4. Step 4: Simplify right side
    69.21x = 6,828.10
  5. Step 5: Solve for x
    x = 6,828.10/69.21
  6. Step 6: Final answer
    x = 98.66

Related Problems

Find fourth proportional to 34.61, 51.58 and 33.10
Half scale
Find fourth proportional to 138.42, 206.30 and 132.39
Double scale
Find fourth proportional to 70.21, 104.64 and 67.20
Similar ratio
Find fourth proportional to 103.82, 154.73 and 99.29
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.