Question

The base of an isosceles triangle is 40cm and its area is 420cm square. Find the length of its equal sides

Answer 1

Hope it helps you man!

Answer 2

The length of its equal sides is 29 cm.

Step-by-step explanation:

Given : The base of an isosceles triangle is 40 cm and its area is 420 cm square.

To Find : The length of its equal sides ?

Solution :

The area of the isosceles triangle is $A=\frac{1}{2}\times b\times h$

Here, Base is b=40 cm

Area is A=420 cm square.

Substitute the values,

$420=\frac{1}{2}\times 40\times h$

$h=\frac{420}{20}$

$h=21\ cm$

Refer the attached figure below.

Let the length of equal sides be AB=AC=x.

As the height is the perpendicular on base so it divide into two right angle triangles with length BD=DC=20 cm.

AD=21 is the height.

Applying Pythagoras theorem in triangle ABD,

$AB^2=AD^2+BD^2$

$x^2=21^2+20^2$

$x^2=441+400$

$x^2=841$

$x=\sqrt{841}$

$x=29$

Therefore, the length of its equal sides is 29 cm.

#Learn more

The area of triangle of base 35cm is 420cm square .find its altitude.

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