Question

find the area of triangle ABC in which AB = 4 cm BC = 5 cm and angle A = 90 degree

Answer 1

This is the answer it is a right angled triangle

Answer 2

The Area of the triangle is 6 sq. cm.

Step-by-step explanation:

Given,

AB = 4 cm      BC = 5 cm

∠A = 90°

We have dawn the triangle for your reference.

Since the triangle is right angled, so we use the Pythagoras Theorem to find the length of AC.

Pythagoras Theorem : The square of the hypotenuse is equal to the sum of square of perpendicular and square of base.

$AB^2+AC^2=BC^2$

On putting the values, we get;

$4^2+AC^2=5^2\\\\16+AC^2=25\\\\AC^2=25-16=9$

On taking square root on both side, we get;

$\sqrt{AC^2}=\sqrt9\\\\AC=3\ cm$

Now Area of the triangle is given by,

$Area = \frac{1}{2}\times base\times height$

Here base = AB = 4 cm

And height = AC = 3 cm

$Area =\frac{1}{2}\times4\times3=2\times3=6\ cm^2$

Hence The Area of the triangle is 6 sq. cm.