This Instructional Activity is a part of the Lesson 10, Unit 5, Grade 6. The term dimensions may be new to English language learners and, as such, may need to be taught and rehearsed. Similarly, the word superscript may be new for English language learners and should be taught or reviewed. How many dimensions does the rectangle have, and what are they? Two dimensions: length and width. What units are used to express area? Square units, such as square centimeters as we had in the Opening Exercise 1.