Home / 319.90-478.20-247

Finding the Fourth Proportional to 319.90, 478.20 and 247

Calculator

Solution

The fourth proportional to 319.90, 478.20 and 247 is: 369.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    319.90 : 478.20 = 247 : x
  2. Step 2: Convert to fraction form
    319.90/478.20 = 247/x
  3. Step 3: Cross multiply
    319.90x = 478.20 × 247
  4. Step 4: Simplify right side
    319.90x = 118,115.40
  5. Step 5: Solve for x
    x = 118,115.40/319.90
  6. Step 6: Final answer
    x = 369.23

Related Problems

Find fourth proportional to 159.95, 239.10 and 123.50
Half scale
Find fourth proportional to 639.80, 956.40 and 494
Double scale
Find fourth proportional to 320.90, 479.69 and 248
Similar ratio
Find fourth proportional to 479.85, 717.30 and 370.50
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.