B Solve the following - In an isosceles triangle- the base angles are equal- The vertex angle is 40- What are the base angles of the triangle- Remember- the sum of three angles of a triangle is 180-

Let the base angle of the triangle be b. Given, a=40^∘, b=c Since, a+b+c= 180^∘ [Angle sum property of a triangle] ⇒ 40^∘+b+b=180^∘ ⇒ 40^∘+2b=180^∘ 2b=180^∘ 40 ...

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Standard VII

Mathematics

Applications (Word Problem)

b Solve the f...

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Question 2(b)
Solve the following :
In an isosceles triangle, the base angles are equal. The vertex angle is $40^{\circ}$ . What are the base angles of the triangle? (Remember, the sum of three angles of a triangle is $180^{\circ}$ .

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Solution

Let the base angle of the triangle be b.
$G i v e n, a = 40^{\circ}, b = c$
Since, a+b+c= $180^{\circ}$ [Angle sum property of a triangle]
$\Rightarrow 40^{\circ} + b + b = 180^{\circ} \Rightarrow 40^{\circ} + 2 b = 180^{\circ} 2 b = 180^{\circ} - 40^{\circ} \Rightarrow 2 b = 140^{\circ} b = \frac{140^{\circ}}{2} \Rightarrow b = 70^{\circ}$
Thus, the base angles of the isosceles triangle are $70^{\circ}$ each.

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Question 2(b) Solve the following : In an isosceles triangle, the base angles are equal. The vertex angle is 40∘. What are the base angles of the triangle? (Remember, the sum of three angles of a triangle is 180∘.

Let the base angle of the triangle be b. Given, a=40∘,b=c Since, a+b+c= 180∘ [Angle sum property of a triangle] ⇒40∘+b+b=180∘⇒40∘+2b=180∘2b=180∘−40∘⇒2b=140∘b=140∘2⇒b=70∘ Thus, the base angles of the isosceles triangle are 70∘ each.

Question 2(b)
Solve the following :
In an isosceles triangle, the base angles are equal. The vertex angle is $40^{\circ}$ . What are the base angles of the triangle? (Remember, the sum of three angles of a triangle is $180^{\circ}$ .