Question

Prove that $tan 4 5^{\circ} = 1$ geometrically.

Approach

In a right-angled isosceles triangle with equal sides, the angle is 45°. Since opposite and adjacent sides are equal, tan 45° = opposite/adjacent = 1.

Step-by-step working

1
Consider an isosceles right triangle with equal legs
1 mark
2
$tan 4 5^{\circ} = \frac{opposite}{adjacent} = \frac{a}{a} = 1$
1 mark

Concepts used

geometric prooftangentisosceles right triangle

Approach

Step-by-step working

Concepts used

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