Answer: An isosceles trapezoid is a trapezoid with two sides of equal length, and those are called legs.
Using the given information that the shorter base is 21, the longer base is 47 and the legs are 50, we can use the Law of Cosines to find the angle between the legs and the longer base.
The Law of Cosines states that for any triangle with sides of length a, b, and c and the angle opposite side c is denoted as C:
c^2 = a^2 + b^2 - 2ab * cos(C)
We will use the legs (a = b = 50) and the longer base (c = 47) as our sides and call the angle we are looking for angle x:
50^2 = 50^2 + 47^2 - 2(50)(47) * cos(x)
Solving for cos(x) will give us the angle x in terms of a cosine. To get the angle x in degrees, we will use the inverse cosine function, which gives the angle in degrees whose cosine is the input value.
cos(x) = (50^2 + 47^2 - 50^2) / (2(50)(47)) = 47/100
x = acos(47/100)
x = approx 126.6
So, the lower base angle in this isosceles trapezoid is approximately 126.6 degrees.
Explanation: