The measure of x correct to the nearest metre is :

1. 70 m

2. 35 m

3. 61 m

4. 140 m

We know that,

cos θ = $\dfrac{\text{Base}}{\text{Hypotenuse}}$

From figure,

In △ ABC,

⇒ cos 30° = $\dfrac{BC}{AB}$

⇒ $\dfrac{\sqrt{3}}{2} = \dfrac{x}{70}$

⇒ x = $\dfrac{70\sqrt{3}}{2} = 35\sqrt{3} = 60.62 \approx 61$ m.

Hence, Option 3 is the correct option.