In any triangle , the sum of any two sides > the third side, so
in triangle abd,
ab +ad > bd **
in triangle bcd,
bc+dc > bd ***
in triangle adc
ad + cd > ac ****
in triangle abc
ab+bc > bd ****
add up *, **, ***, and ****
2ab + 2bc + 2dc + 2ad > 2bd + 2ac
divid by 2:
ab + bc + dc + ad > bd + ac , as needed
add ** and ***
ab+bc+ad+cd >
show that in a quadrilateral abcd , ab+bc+cd+da>ac+bd .
2 answers
In the quadrilateral ABCD, AB is represented by the equation y=1 where -1 < x < 1, DC is represented by the equation y = -1 where -1 < x < 2.
1) What type of quadrilateral is this? Use the equations to find coordinates for A B C and D.
2) What is the perimeter?
3) What is the area?
1) What type of quadrilateral is this? Use the equations to find coordinates for A B C and D.
2) What is the perimeter?
3) What is the area?