Question

if each angle of triangle is less than 5he sum of other two . Show that the triangle is acute angled for class 7th (b)​

Answer 1

Step-by-step explanation:

Let ∠A<∠B+∠C. Then,

2∠A<∠A+∠B+∠C⇒2∠A<180

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⇒∠A<90

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Similarly, we obtain ∠B<90

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and ∠C<90

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=> Each angle of the triangle is less than 90° and hence it is an acute-angled triangle.

Answer 2

Answer:

let ABC be a triangle

Step-by-step explanation:

angle A < angle B+ angle C --- equation 1

we know sum of all angles of a triangle is 180°

now adding angke A to both sides of equation 1

2 angle A < angle A+ angle B + angle C

which gives 2 angle A < 180°

gives angle A<90°

thus angle B as well as angle C < 90°

thus it is an acute triangle since all angles are acute angles