ABC and ACD are both right angled triangles

Answer:
a. Pythagorous theorem
b. 13.9 cm
Step-by-step explanation:
a. By pythagorous theorem,
AC = [tex]\sqrt{12^{2} + 5^{2}}[/tex] cm = 13 cm
b. By pythagorous theorem,
AD = [tex]\sqrt{13^{2}+5^{2}}[/tex] cm = 13.9 cm
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