Find solutions to your questions with the help of IDNLearn.com's expert community. Join our knowledgeable community to find the answers you need for any topic or issue.

ΔABC is an equilateral triangle with AD perpendicular to BC. Prove that ΔADB ≅ ΔADC.

Sagot :

Step-by-step explanation:

An equilateral triangle means all sides are congruent.

AB≅BC≅AC

All angles are also congruent.

∠ABC≅∠BCA≅∠CAB

AD being perpendicular makes it a bisector of both BC and ∠CAB.

BD≅CD

∠BAD≅∠CAD

Now, there are multiple ways to prove that ΔADB≅ΔADC. All 3 sides and all 3 angles of both triangles are congruent, so you could do it however you want.

1) ASA (one of the possible ASA combinations)

  • ∠ABD ≅ ∠ACD because this is an equilateral triangle
  • BD ≅ CD because AD bisects BC
  • ∠BDA ≅ ∠CDA because AD is perpendicular to BC, both 90°

2) HL (again, one of the multiple possible HL combinations)

  • AD is perpendicular to BC, creating 2 right triangles
  • AB ≅ AC because ΔABC is equilateral
  • AD ≅ DA by the reflexive property, it is congruent to itself

There are many more but I won't write them all out.

View image Cinderofsoulsss