Find the area of triangle at the points A (1,8), B(4,7) and C(5/2, 15/2)?

To find the area of a triangle with the given coordinates, we can use the formula for the area of a triangle given its vertices:

Area = 1/2 * |x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)|

In this case, the coordinates of the vertices are:
A(1,8), B(4,7), C(5/2, 15/2)

Plugging in the coordinates into the formula, we get:
Area = 1/2 * |1(7 - 15/2) + 4(15/2 - 8) + 5/2(8 - 7)|
Area = 1/2 * |1(1/2) + 4(1/2) + 5/2|
Area = 1/2 * |1/2 + 2 + 5/2|
Area = 1/2 * |1/2 + 4/2 + 5/2|
Area = 1/2 * |10/2|
Area = 1/2 * 5
Area = 5/2
Area = 2.5

Therefore, the area of the triangle with vertices A(1,8), B(4,7), and C(5/2, 15/2) is 2.5 square units.

The area of a triangle with vertices (x1, y1), (x2, y2), and (x3, y3) is given by the formula:
Area = 1/2 |(x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2))|

Using this formula, we can find the area of the triangle with vertices A(1,8), B(4,7), and C(5/2, 15/2):
Area = 1/2 |(1(7 - 15/2) + 4(15/2 - 8) + 5/2(8 - 7))|
Area = 1/2 |(1(-1/2) + 4(7/2) + 5/2(1))|
Area = 1/2 |(-1/2 + 14 + 5/2)|
Area = 1/2 |17/2|
Area = 17/4 square units

Therefore, the area of the triangle is 17/4 square units.