Answer:
AB = 14.0 cm
Step-by-step explanation:
Pythagora's Theorem
In a right triangle with a hypotenuse of length H and legs of lengths L and W, then it's satisfied the equation:
[tex]H^2 = L^2+W^2[/tex]
The diagram shows a wedge ABCDEF and it's required to calculate the length of the side AB.
Note the triangle FCB is right at C, where side length is the hypotenuse:
[tex]BF^2=13^2+6^2[/tex]
[tex]BF^2=169+36=205[/tex]
Triangle ABF is right at B and 20 cm is the hypotenuse, thus:
[tex]20^2 =AB^2+BF^2[/tex]
Solving for AB:
[tex]AB^2=20^2-BF^2[/tex]
[tex]AB^2=20^2-205[/tex]
[tex]AB^2=400-205=195[/tex]
[tex]AB=\sqrt{195}[/tex]
AB = 14.0 cm
