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Given below are two statements:

Statement I: In △ABC,AB=63 cm,AC=12 cm\triangle A B C, A B=6 \sqrt{3} \mathrm{~cm}, A C=12 \mathrm{~cm} and BC=6 cmB C=6 \mathrm{~cm}, then angle B=90∘B=90^{\circ}

Statement II: In △ABC\triangle A B C, is an isosceles with AC=BCA C=B C. If AB2=2AC2A B^{2}=2 AC^{2}, Then angle C=90∘C=90^{\circ}

In the light of the above statement, choose the correct answer form the question below.

Solution

✅ Correct Option: 1

Statement I:

Given: AB=63AB = 6\sqrt{3} cm, AC=12AC = 12 cm, BC=6BC = 6 cm

Using Pythagorean theorem if angle B = 90°:

AB2+BC2=AC2AB^2 + BC^2 = AC^2

(63)2+62=122(6\sqrt{3})^2 + 6^2 = 12^2

108+36=144108 + 36 = 144

144=144144 = 144 ✓

Therefore Statement I is true.

Statement II:

Given isosceles triangle where AC=BCAC = BC

And AB2=2AC2AB^2 = 2AC^2

In isosceles triangle, base angles are equal.

Let base angles each be xx

Then C=180°−2xC = 180° - 2x

If AB2=2AC2AB^2 = 2AC^2, this means cos⁡C=0\cos C = 0

Therefore C=90°C = 90°

Therefore Statement II is also true.

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