# The base of an isosceles triangle is 26 cm, the angle at the base is 56 degrees. Find the perimeter of this triangle.

July 28, 2021 | education

| Let’s mentally draw the height to the base of our triangle.

As we know from the school curriculum in geometry, it will be in this triangle and the median.

Then the leg adjacent to the 56 ° angle will be equal to:

26: 2 = 13.

Let’s find out how many centimeters one of the unknown sides of our triangle will be equal to, which is the hypotenuse in the resulting right-angled triangle:

13: cos 56 °;

cos 56 ° ≈ 0.559;

13: 0.559 ≈ 23.26.

Then the perimeter of our triangle is:

26 + 2 * 23.26 = 72.52.

Answer: 72.52 cm.

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