Question

An umbrella top is composed of 8 equal triangles of fabric. What is the sum of the interior angles of the umbrella top?

Answer 1

480 cm2

Explanation:

8 isosceles triangles of sides 13cm,13cm,10cm

By Heron's Formula,

Area =

s(s−a)(s−b)(s−c)

Where s=

2

a+b+c

s=

2

13+13+10

=18

Area of triangle =

18×(18−13)×(18−13)×(18−10)

(Heron's formula)

Area of triangle =

18×5×5×8

=5

144

Area of triangle =60cm

2

Area of cloth made of 8 triangles =60×8

=480cm2