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The coordinates of points a, B and C are (3,0), (1, 3 under the root sign) and (0,1) respectively (4 / 4) the coordinates of points a, B and C are (3,0), (1, 3 under the root sign) and (0,1) respectively to find the area of the quadrilateral oabc
Do BD ⊥ OA at point d through B
In this way, oabc is divided into ODBC and abd
S□ODBC=（OC+BD)×OD×1/2=（√3+1）/2
S△ABD=BD×DA×1/2=√3
S□ODBC+S△ABD=（√3+1）/2+√3=（3√3+1）/2
The area of oabc is (3 √ 3 + 1) / 2
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As shown in the figure, given that the coordinates of a, B and C are a [1, radical 5], B [2, radical 5], C [radical 10,0], the area of trapezoid oabc can be calculated
[accurate to 0.1]
S trapezoid = [(2-1) + √ 10] * √ 5 / 2 ≈ 4.7
As shown in the figure, the coordinates of a, B and C are a [- radical 3,1], B [0, radical 5], C [- 2,0]. Calculate the area of the quadrilateral acob
To two decimal places]
If OA is connected, OB = 5, OC = 2, s quadrilateral acob = s △ AOC + s △ AOB = 2x1 / 2 + 5x √ 3 / 2 = 1 + 5 √ 3 / 2
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