Q1 of 97 Page 205

In an equilateral ∆ABC, find ∠A.

We know that,

In any equilateral triangle all the angles are equal


Let the three angles of the triangle ∠A, ∠B and ∠C be x


∴ x + x + x = 180°


3x = 180°


x =


x = 60


Hence, ∠A = 60o


More from this chapter

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28

Fill in the blanks with < or >.

(A) (Sum of any two sides of a triangle)………… (the third side)


(B) (Difference of any two sides of a triangle)………… (the third side)


(C) (Sum of three altitudes of a triangle)………… (sum of its three sides)


(D) (Sum of any two sides of a triangle)…….. (twice the median to the 3rd side)


(E) (Perimeter of a triangle)…………. (Sum of its three medians)

 29

Fill in the blanks:

(A)Each angle of an equilateral triangle measures……………..


(B) Medians of an equilateral triangle are…………


(C) In a right triangle the hypotenuse is the ……….side.


(D) Drawing a ∆ABC with AB=3cm, BC=4cm and CA=7cm is………..

 2

In a ∆ABC, if AB=AC and ∠B=65°, find ∠A.

 3

In a right ∆ABC, ∠B=90°. Find the longest side.