Home / 84.40-126.48-72.80

Finding the Fourth Proportional to 84.40, 126.48 and 72.80

Calculator

Solution

The fourth proportional to 84.40, 126.48 and 72.80 is: 109.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.40 : 126.48 = 72.80 : x
  2. Step 2: Convert to fraction form
    84.40/126.48 = 72.80/x
  3. Step 3: Cross multiply
    84.40x = 126.48 × 72.80
  4. Step 4: Simplify right side
    84.40x = 9,207.74
  5. Step 5: Solve for x
    x = 9,207.74/84.40
  6. Step 6: Final answer
    x = 109.10

Related Problems

Find fourth proportional to 42.20, 63.24 and 36.40
Half scale
Find fourth proportional to 168.80, 252.96 and 145.60
Double scale
Find fourth proportional to 85.40, 127.98 and 73.80
Similar ratio
Find fourth proportional to 126.60, 189.72 and 109.20
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.