Home / 98.80-136.16-78

Finding the Fourth Proportional to 98.80, 136.16 and 78

Calculator

Solution

The fourth proportional to 98.80, 136.16 and 78 is: 107.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.80 : 136.16 = 78 : x
  2. Step 2: Convert to fraction form
    98.80/136.16 = 78/x
  3. Step 3: Cross multiply
    98.80x = 136.16 × 78
  4. Step 4: Simplify right side
    98.80x = 10,620.48
  5. Step 5: Solve for x
    x = 10,620.48/98.80
  6. Step 6: Final answer
    x = 107.49

Related Problems

Find fourth proportional to 49.40, 68.08 and 39
Half scale
Find fourth proportional to 197.60, 272.32 and 156
Double scale
Find fourth proportional to 99.80, 137.54 and 79
Similar ratio
Find fourth proportional to 148.20, 204.24 and 117
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.