You learned a rectangle
and its properties when you
were at an elementary school.
To recall them, discuss the
following tasks with your
a. Find something around you in which the surface
has a shape of book pages.
b. Suppose one of your book pages has a
rectangular shape as shown in the figure below.
What are the elements of the rectangle ABCD?
What are you going
To define a rectangle.
To discover the
formula of the
perimeter and area of
Work in Groups
Materials: paper, scissors, a ruler, and a protractor.
1. Take a piece of paper forming a rectangle as in
the figure on the right.
2. Cut the paper into 2 of the same measure and
share them with your classmate(s).
3. Name each rectangle ABCD.
4. Connect point A with point C, point B with point D, and mark the point of the intersection
from those 2 lines and name it.
5. Use ruler to measure the lengths of sides and diagonals of the rectangle ABCD!
OC =.......cm OD =........cm
6. What is the relation between the lengths of AB and DC , AD and BC , and AC and BD ?
7. What is the relation of the lengths of OA , OB , OC , and OD ?
8. Use the protractor to measure the following angles.
∠DAB =.......° ∠ABC =.......° ∠BCD =.......° ∠CDA =.......°
9. What is the relation of ∠DAB, ∠ABC, ∠BCD, and ∠CDA?
10. Cut all corners of rectangle ABCD and then fit together side by side. Do the
four angles form a whole turned angle or 360°?
11. Based on the activity, what can you conclude? Explain.
Mini - Lab
Mathematics for Junior High School Year 7 / 303
The elements of rectangle ABCD are sides AB , BC , CD , and
AD ; diagonal, that is AC dan BD ; and angles ∠A, ∠B, ∠C, and
Properties of a rectangle are that:
it has equal o