Question 1 - Figure it out - Page 154 - Chapter 7 Class 7 - A tale of three Intersecting Lines (Ganit Prakash)

Transcript

Question 1 We checked by construction that there are no triangles having sidelengths 3 cm, 4 cm and 8 cm; and 2 cm, 3 cm and 6 cm. Check if you could have found this without trying to construct the triangle. We need to check Triangle Inequality Which says Sum of Two Sides > Third Side We don’t need to check all the combinations We just check if Sum of smaller sides > Largest side Let’s do this one by one Sides 3 cm, 4 cm and 8 cm Here, Sum of smaller two sides = 3 + 4 = 7 And, Largest side = 8 Now, 7 < 8 This does not satisfy triangle inequality ∴ Triangle does not exist Sides 2 cm, 3 cm and 6 cm Here, Sum of smaller two sides = 2 + 3 = 5 And, Largest side = 6 Now, 5 < 6 This does not satisfy triangle inequality ∴ Triangle does not exist