Question

Q11. Plot the points (3,4), (-2,4) and (-1,-1) on Cartesian plane and find the area of the triangle obtained on joining these points​

Answer 1

Answer:

• The graph* for this question is given in attachment.
• Area of triangle = 12.5 sq.units

Step-by-step explanation:

Area of triangle = 1/2 × (Base) × (Height)

As it can be observed from the graph,

• Base = Distance between point (-2, 4) to (3, 4) = 5 units
• Height = 5 units

⇒ Area of triangle = 1/2 × 5 × 5

⇒ Area of triangle = 1/2 × 25

⇒ Area of triangle = 12.5 sq.units

∴ Area of triangle = 12.5 sq.units

*Graph attached is made with Desmos Graph

REMEMBER:

• When the base and height of the triangle cannot be easily identified from the graph, then use Heron's formula for finding the area of the triangle from sides of the triangle.
• s = (a + b + c) ÷ 2

where:

s is the semi-perimeter.

• Then area = √[(s) (s - a) (s - b) (s - c)]