Home / 280.80-387-207

Finding the Fourth Proportional to 280.80, 387 and 207

Calculator

Solution

The fourth proportional to 280.80, 387 and 207 is: 285.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.80 : 387 = 207 : x
  2. Step 2: Convert to fraction form
    280.80/387 = 207/x
  3. Step 3: Cross multiply
    280.80x = 387 × 207
  4. Step 4: Simplify right side
    280.80x = 80,109
  5. Step 5: Solve for x
    x = 80,109/280.80
  6. Step 6: Final answer
    x = 285.29

Related Problems

Find fourth proportional to 140.40, 193.50 and 103.50
Half scale
Find fourth proportional to 561.60, 774 and 414
Double scale
Find fourth proportional to 281.80, 388.38 and 208
Similar ratio
Find fourth proportional to 421.20, 580.50 and 310.50
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.