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An isosceles triangle has a base of 22 cm and a vertex angle of 36˚. Find the perimeter of the triangle.

a) 44 cm
b) 58 cm
c) 66 cm
d) 72 cm

User Turgay
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1 Answer

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Final answer:

An isosceles triangle with a base of 22 cm and a vertex angle of 36˚ has a perimeter of approximately 99.734 cm.

Step-by-step explanation:

An isosceles triangle has two equal sides and two equal angles. Since the triangle has a vertex angle of 36˚, the other two angles must each be (180˚ - 36˚) / 2 = 72˚. The perimeter of the triangle is the sum of the lengths of all three sides, which can be calculated as:

Perimeter = 22 cm + 22 cm + 2 * (side length of triangle)

We can use trigonometry to find the side length of the triangle. In a right triangle formed by the base and one of the legs of the triangle, with the vertex angle as the right angle, the side length can be calculated as:

Side length = base / cos(vertex angle)

Substituting the values, we get:

Side length = 22 cm / cos(36˚)

Calculating this value, we get approximately 27.867 cm.

Finally, plugging in this value in the perimeter formula, we have:

Perimeter = 22 cm + 22 cm + 2 * 27.867 cm

Perimeter ≈ 22 cm + 22 cm + 55.734 cm = 99.734 cm.

Therefore, the answer is approximately 99.734 cm.

User Lahib
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