Question

If the vertex angle of an isosceles triangle is 40 degrees then the measure of other two angles will be?

Answer 1

Answer:

The two angles will be 70° & 70° respectively .

Step-by-step explanation:

According to the Question

It is given that ,

• Vertex angle = 40°
• Types of Triangle = Isosceles triangle .

As we know that 2 sides in Isosceles triangle are equal . Therefore , 2 angles will also be equal .

Let the two equal angles be a.

Now,

we know that Sum of angles in triangle be 180°

• Sum of Angles = 180°

substitute the value we get

→ a + a + 40° = 180°

→ 2a + 40° = 180°

→ 2a = 180° - 40°

→ 2a = 140°

→ a = 140°/2

→ a = 70°

• Hence, both angles of isosceles triangle will be 70° respectively .

Answer 2

Answer:

Given :-

• The vertex angle of an isosceles triangle is 40°.

To Find :-

• What is the measure of other two angles.

Solution :-

Let,

$\mapsto \bf The\: measure\: of\: an\: isosceles\: triangle =\: x$

As we know that :

$\footnotesize\bigstar\: \: \boxed{\bold{\pink{Sum\: of\: three\: angles\: of\: a\: triangle =\: 180^{\circ}}}}\: \: \bigstar$

According to the question by using the formula we get,

$\implies \sf x + x + 40^{\circ} =\: 180^{\circ}$

$\implies \sf 2x + 40^{\circ} =\: 180^{\circ}$

$\implies \sf 2x =\: 180^{\circ} - 40^{\circ}$

$\implies \sf 2x =\: 140^{\circ}$

$\implies \sf x =\: \dfrac{\cancel{140^{\circ}}}{\cancel{2}}$

$\implies \sf x =\: \dfrac{70^{\circ}}{1}$

$\implies \sf\bold{\red{x =\: 70^{\circ}}}$

Hence, the measure of an isosceles triangle is 70°.

As we know that,

• In an isosceles triangle two sides are equal is called isosceles triangle.
• The two angles opposite to the equal sides are equal.

If, the vertex of an isosceles triangle is 40°, then the two sides of an isosceles triangle will be 70° and 70°.

${\small{\bold{\underline{\therefore\: The\: measure\: of\: other\: two\: isosceles\: triangle\: is\: 70^{\circ}\: and\: 70^{\circ}\: respectively\: .}}}}$

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★ EXTRA INFORMATION ★

❒ Types Of Triangle :

➲ Based on their sides :

• Equilateral Triangle
• Isosceles Triangle
• Scalene Triangle

➲ Based on their angles :

• Acute-angled Triangle
• Obtuse-angled Triangle
• Right-angled Triangle