CLASS9: To verify the mid-point theorem of triangle using paper cutting and pasting.
Sum1 pls send their activity frm their math labmanualNB...im too lazy to do it
Answers
Answer: Here is your activity,
Step-by-step explanation:
Objective
To verify that in a triangle, the line joining the mid-points of any two sides is parallel to the third side and half of it by paper folding and pasting.
Prerequisite Knowledge
Concept of angles, triangles and mid-points.
Concept of corresponding angles: If a transversal cuts two straight lines such that their corresponding angles are equal, then the lines are parallel.
Materials Required
Glazed papers, a pair of scissors, pencil, eraser, gluestick, white sheet.
Procedure
Draw ∆ABC on the yellow glazed paper of any measurement and paste it on white sheet.
Find mid-points of the two sides (say AB and AC) of a triangle by paper folding. We obtain D and E as mid-points of AB and AC respectively in 1st triangle.
CBSE Class 9 Maths Lab Manual – Mid-point Theorem 1
Draw horizontal line DE. Similarly find mid-point of side BC and name it F as shown in fig. (ii).
CBSE Class 9 Maths Lab Manual – Mid-point Theorem 2
Trace the ∆ABC on tracing paper and cut ∆ABC along line DE as shown in fig.(iii).
CBSE Class 9 Maths Lab Manual – Mid-point Theorem 3
Paste this cut out of triangle ADE [fig. (iii) ] on ∆ABC of fig. (ii) such that AE coincides with EC and ED lies on CB and point D coincides with F as shown in fig. (iv).
CBSE Class 9 Maths Lab Manual – Mid-point Theorem 4
∆ADE completely covers ∆EFC.
Observation
We observe that ∆ADE exacdy overlaps ∆EFC.
∴ ∠1 = ∠2 (corresponding angles)
AC is any transversal line intersecting the lines DE and BC.
∴ DE || BC.
By paper folding we observe that, in fig (iv) F, the mid point of BC coincides with D.
∴ DE = FC (As DE superimposes on FC)
or DE = FC = BC2
Result
Hence, it is verified that the line joining the mid-points of two sides of a triangle is parallel to third side and half of it.
Hope this Helps!!!
Don't be lazy !!
Answer:
your answer
Step-by-step explanation:
Prerequisite Knowledge
Concept of angles, triangles and mid-points.
Concept of corresponding angles: If a transversal cuts two straight lines such that their corresponding angles are equal, then the lines are parallel.
Materials Required
Glazed papers, a pair of scissors, pencil, eraser, gluestick, white sheet.
Procedure
Draw ∆ABC on the yellow glazed paper of any measurement and paste it on white sheet.
Find mid-points of the two sides (say AB and AC) of a triangle by paper folding. We obtain D and E as mid-points of AB and AC respectively in 1st triangle.
CBSE Class 9 maths lab manual – Mid-point Theorem 1
Draw horizontal line DE. Similarly find mid-point of side BC and name it F as shown in fig. (ii).
CBSE Class 9 Maths Lab Manual – Mid-point Theorem 2
Trace the ∆ABC on tracing paper and cut ∆ABC along line DE as shown in fig.(iii).
CBSE Class 9 Maths Lab Manual – Mid-point Theorem 3
Paste this cut out of triangle ADE [fig. (iii) ] on ∆ABC of fig. (ii) such that AE coincides with EC and ED lies on CB and point D coincides with F as shown in fig. (iv).
CBSE Class 9 Maths Lab Manual – Mid-point Theorem 4
∆ADE completely covers ∆EFC.
Observation
We observe that ∆ADE exacdy overlaps ∆EFC.
∴ ∠1 = ∠2 (corresponding angles)
AC is any transversal line intersecting the lines DE and BC.
∴ DE || BC.
By paper folding we observe that, in fig (iv) F, the mid point of BC coincides with D.
∴ DE = FC (As DE superimposes on FC)
or DE = FC = BC2
Result
Hence, it is verified that the line joining the mid-points of two sides of a triangle is parallel to third side and half of it.
