Skip to content
LessonPrint

Find the Missing Side is a free printable Grade 3 maths worksheet on working backwards from the area, aligned to Common Core standard 3.MD.C.7. It prints 8 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two pupils in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 23 of 25 · the same problems every time you open this link.

Next set

One paper per pupil

12345678910111213141516171819202122232425

Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

Find the Missing Side

3.MD.C.7

NameDate

Work out the missing side.

1.
Area is 77, one side is 11. Other side =
2.
Area is 78, one side is 13. Other side =
3.
Area is 96, one side is 12. Other side =
4.
Area is 112, one side is 14. Other side =
5.
Area is 80, one side is 10. Other side =
6.
Area is 84, one side is 14. Other side =
7.
Area is 99, one side is 11. Other side =
8.
Area is 88, one side is 11. Other side =

LessonPrint · 3.MD.C.7 · Set 23 · free to copy for classroom use

Answer key — Find the Missing Side

Set 23. Prints on its own sheet.

  1. 1.7
  2. 2.6
  3. 3.8
  4. 4.8
  5. 5.8
  6. 6.6
  7. 7.9
  8. 8.8

Last reviewed 2026-09-05. Aligned to 3.MD.C.7 of the Common Core State Standards for mathematics.