Correct Answer - Option 2 : 28

**Given:**

Area of triangle = 280 cm^{2}

Ratio of height to its base = 7:5

**Formula Used:**

Area of triangle = ½ × Base × Height

**Calculation:**

Suppose, the base and height of the triangle is 5x and 7x, respectively.

Area of Triangle = ½ × 5x × 7x

⇒ 280 = ½ × 35x^{2}

⇒ 35x^{2} = 560

⇒ x^{2} = 16

⇒ x = √16

⇒ x = 4

**∴ The length of height of triangle = 7x = 28 cm**