This question was previously asked in

UPSSSC Chakbandi Lekhpal Official Paper 3 (Held on : 1 Oct 2019 Shift 1)

- Sin A = Sin B
- Sin A = -Sin B
- Sin A = Cos B
- Sin A = -Cos B

Option 3 : Sin A = Cos B

**Given:**

∠C =90°

**Concept used:**

Sinθ = Perpendicular/Hypotenuse

Cosθ = Base/Hypotenuse

**Calculation:**

Let ∠A be θ

So, ∠B = 180 - (90° + θ)

⇒ ∠B = (90° - θ)

⇒ SinA = Sinθ ----(1)

⇒ CosB = Cos(90° - θ)

⇒ CosB = Sinθ ----(2)

Now, from equation (1) and (2), we get

⇒ SinA = CosB

**∴ The required answer is SinA = CosB.**

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