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Observe the given figure and state the three pairs of equal parts in triangles ABC and DBC. Is ∆ABC ≅ ∆DCB? Why? Is AB = DC? Why? Is AC = DB? Why?

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Question

Observe the given figure and state the three pairs of equal parts in triangles ABC and DBC.

  1. Is ∆ABC ≅ ∆DCB? Why?
  2. Is AB = DC? Why?
  3. Is AC = DB? Why?

Sum
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Solution

i. In ∆ABC and ∆DCB,

∠ABC = ∠DCB = 40° + 30 = 70°  ...(Given)

∠ACB = ∠DBC = 30°  ...(Given)

BC = CB  ...(Common)

∴ ∆ABC ≅ ∆DCB  ...(ASA criterion)

ii. Yes, by using part (i), we get

AB = DC  ...(By C.P.C.T.)

iii. Yes, by using (i) part, we get

AC = DB  ...(By C.P.C.T.)

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Chapter 6: Triangles - Exercise [Page 184]

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NCERT Exemplar Mathematics Exemplar Class 7
Chapter 6 Triangles
Exercise | Q 153. | Page 184

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