Question

19. The area an isoceles triangle having base 4cm and the length of one of the equal sides 5cm is: ​

Answer 1

Answer:

Sides -

a = 4cm

b = 5cm

c = 5cm

Formula - Herons Formula

S = (a+b+c)/2

= (4+5+5)/2

= 14/2

= 7cm

A = √s (s-a) (s-b) (s-c)

= √ 7 (7-4) (7-5) (7-5)

= √ 7 x 3 x 2 x 2

= √ 7 x 3 ( 2 x 2 )

= 2 √ 7 x 3

= 2√21

Area is 2√21 cm²

Answer 2

Answer:

S= semiperimeter

S=2a+b+c

=24+8+8=10

By Heron's Formula,

A(ΔABC)=S(S−a)(S−b)(S−c)

=10(10−4)(10−8)(10−8)

=10×6×2×2

=260

=2×4×15=2×215

=415cm2