Observe the above figure and answer the question.
The length of AB is:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \(\sqrt{149}\) cm
The diagonal AC splits ABCD into two right triangles, ADC (right angle at D) and ACB (right angle at C). AC is found from the first by Pythagoras’ theorem, and AB from the second.
In triangle ADC: \(AC=\sqrt{6^2+8^2}=\sqrt{100}=10\) cm
In triangle ACB: \(AB=\sqrt{AC^2+CB^2}=\sqrt{100+49}=\sqrt{149}\) cm