Find the area of the isosceles trapezoid below by using the area formulas for rectangles and triangles.
a = 10 cm, b = 15 cm, and c = 5 cm
*picture not drawn to scale
A.
250 cm2
B.
200 cm2
C.
175 cm2
D.
800 cm2
To find the area of the isosceles trapezoid, we can split it into a rectangle and two right triangles.
The base of the trapezoid is 15 cm, so the base of the rectangle is 15 cm. The height of the trapezoid is 5 cm, corresponding to one of the sides of the right triangles.
The rectangle has an area of base * height = 15 cm * 5 cm = 75 cm²
Each right triangle has a base of 10 cm (half of the top base of the trapezoid, which is 20 cm) and a height of 5 cm.
The area of each triangle is (1/2) * base * height = (1/2) * 10 cm * 5 cm = 25 cm²
Since there are two right triangles, the total area of both triangles is 50 cm²
Adding the area of the rectangle and the two triangles, the total area of the isosceles trapezoid is 75 cm² + 50 cm² = 125 cm²
Therefore, the correct answer is not among the options provided.