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Distance Formula Worksheet Answer Key – Grade 8

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Last updated: October 22, 2026 · Written by the Math Made Easy math teachers

Grade 8 Math Worksheet Answer Keys – Mathbot, the Math Made Easy robot coach, with free printable worksheet answer keys for Grade 8

Looking for a distance formula worksheet answer key? Then this answer key gives every step of the Grade 8 worksheet on Finding Distance Between Points on a Grid. Each solution lists the two legs, applies the distance formula, and states the length with units. Check that the horizontal and vertical differences match the figure, and keep roots exact until the final rounding step.

Standards: 8.G.B.8 · Level: Grade 8

Problem 2 Down a column

The x-coordinates match: |9 − (−6)| = 15.

The distance is 15 units.

Problem 3 From the origin

d = √(36² + 77²) = √(1,296 + 5,929) = √7,225 = 85.

The distance is 85 units.

Problem 4 Not a whole number

Legs: 2 − (−4) = 6 and −2 − 7 = −9, so the vertical leg is 9.

d = √(36 + 81) = √117 ≈ 10.82.

The distance is about 10.8 units.

Problem 5 Read the graph

K(−3, 5) and L(4, −3). Horizontal leg: 7. Vertical leg: 8.

d = √(49 + 64) = √113 ≈ 10.63.

−5−4−3−2−1123456−5−4−3−2−11234567xyK(−3, 5)L(4, −3)78
Legs 7 and 8, so KL = √113.

√113 ≈ 10.6 units

Problem 6 Twenty units

Legs: 10 − (−6) = 16 and 9 − (−3) = 12.

d = √(256 + 144) = √400 = 20.

20 units

Problem 7 Equal legs

Legs: |−4 − 2| = 6 and |−1 − (−7)| = 6.

d = √(36 + 36) = √72 = 6√2 ≈ 8.49.

6√2 ≈ 8.5 units

Problem 8 Right triangle on a grid

AB² = 3² + 1² = 10. BC² = 1² + 3² = 10. AC² = 2² + 4² = 20.

AB² + BC² = 10 + 10 = 20 = AC².

1234567−2−112345xyABC
Triangle ABC.

Yes, it is a right triangle with the right angle at B

Problem 9 Perimeter of a rectangle

Width: 4 − (−2) = 6. Height: 2 − (−3) = 5.

Perimeter: 2(6 + 5) = 22.

22 units

Problem 10 Perimeter of a triangle

Horizontal side: 5. Vertical side: 12. Slanted side: √(25 + 144) = √169 = 13.

Perimeter: 5 + 12 + 13 = 30.

30 units

Problem 11 Triangle perimeter from a graph

DE = 6 and EF = 5 by counting. DF = √(6² + 5²) = √61 ≈ 7.81.

Perimeter: 6 + 5 + 7.81 = 18.81.

About 18.8 units

Problem 12 Find the missing coordinate

(x − 2)² + (9 − 1)² = 10², so (x − 2)² + 64 = 100.

(x − 2)² = 36, so x − 2 = 6 or x − 2 = −6.

x = 8 or x = −4

Problem 13 Isosceles check

AB = 6. AC = √(3² + 6²) = √45. BC = √(3² + 6²) = √45.

AC = BC, so the triangle is isosceles.

Perimeter: 6 + 2√45 = 6 + 13.42 = 19.42.

Isosceles; perimeter ≈ 19.4 units

Problem 14 Trapezoid perimeter

AB = 4 (horizontal). DA = 4 (vertical). CD = 7 (horizontal).

BC = √((4 − 1)² + (2 − (−2))²) = √(9 + 16) = 5.

Perimeter: 4 + 5 + 7 + 4 = 20.

20 units

Problem 15 Which is closer?

OA² = 49 + 25 = 74. OB² = 36 + 36 = 72.

Since 72 is less than 74, B is closer (√72 ≈ 8.49 compared with √74 ≈ 8.60).

Point B is closer

Problem 16 Hiking map

Legs: 3 − (−5) = 8 and 2 − (−3) = 5.

d = √(64 + 25) = √89 ≈ 9.43.

About 9.4 miles

Problem 17 Drone delivery

Legs: 9 − (−6) = 15 and 6 − (−2) = 8.

d = √(225 + 64) = √289 = 17 units.

17 · 0.25 = 4.25.

4.25 miles

Problem 18 Garden fence

Sides in units: 8, 15, and √(64 + 225) = 17. Perimeter: 8 + 15 + 17 = 40 units.

40 · 2 = 80 feet, and 80 · $3.50 = $280.

$280

Problem 19 Robot route

AB = √(3² + 6²) = √45 ≈ 6.71. BC = √(6² + 6²) = √72 ≈ 8.49.

Route: 6.71 + 8.49 = 15.19. Straight path AC = 4 − (−5) = 9.

Savings: 15.19 − 9 = 6.19.

Route ≈ 15.2 units; the straight path is about 6.2 units shorter

Problem 20 Rhombus on the grid

WX = √(5² + 2²) = √29. XY = √(5² + 2²) = √29. YZ = √(5² + 2²) = √29. ZW = √(5² + 2²) = √29.

All sides equal √29 ≈ 5.385.

Perimeter: 4√29 ≈ 21.54.

All sides are √29; perimeter ≈ 21.5 units