Prove

Question

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Answer 1

This question can be solved using congruent triangles rule or Cosine rule.

1. Congruent triangles rule (more simple)

2. Cosine rule

Comments

Bruh,professional answer...

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Don’t learn maths in that way, please remember the easier  way you learned before…this question just need to use the property of congruent triangle to solve only…

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thanks for the pointer, i have uploaded the simpler method using congruent triangle rule

Answer 2

I think answer is ...

The angle of the △ABC and △DEF is same because it's collinear with AB and DE.

If you agree with my answer , please pick up my answer. Thanks.

我的答案可能会有错误，因为我平常是用马来文来回答的。抱歉哈~

Answer 3

对不起哈我用的是华文版本的

AB=DE（已知）

BE=CF（已知）

∠ABC=∠DEF

∴▲ABC≌▲DEF（SAS）