What is the area of a decagon with a side length of 4cm?
4cm
so sussy balls
To find the area of a decagon (a polygon with ten sides) with a given side length, you can use the following formula:
Area = (5/4) * (s^2) * cot(π/10)
where s is the length of a side.
In this case, the given side length is 4 cm, so we can substitute s = 4 into the formula:
Area = (5/4) * (4^2) * cot(π/10)
To evaluate the cotangent function, you can use a scientific calculator or an online trigonometric calculator.
After calculating cot(π/10) and substituting all the known values into the formula, you will get the area of the decagon.
You would have 10 congruendt isosceles triangles,
each with a top angle of 36° , and equal base angles of
72°
We need the height:
height/2 = tan 72°
height = 2tan72°
area of each triangle = (1/2)base x height
= (1/2)(4)(2tan72°) = 4tan72°
so area of decagon = 10(4tan72°) = ....
you do the button-pushing.