Home / 648.50-971.28-387.99

Finding the Fourth Proportional to 648.50, 971.28 and 387.99

Calculator

Solution

The fourth proportional to 648.50, 971.28 and 387.99 is: 581.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    648.50 : 971.28 = 387.99 : x
  2. Step 2: Convert to fraction form
    648.50/971.28 = 387.99/x
  3. Step 3: Cross multiply
    648.50x = 971.28 × 387.99
  4. Step 4: Simplify right side
    648.50x = 376,846.93
  5. Step 5: Solve for x
    x = 376,846.93/648.50
  6. Step 6: Final answer
    x = 581.11

Related Problems

Find fourth proportional to 324.25, 485.64 and 194.00
Half scale
Find fourth proportional to 1,297, 1,942.56 and 775.98
Double scale
Find fourth proportional to 649.50, 972.78 and 388.99
Similar ratio
Find fourth proportional to 972.75, 1,456.92 and 581.99
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.