Question

Find the area of a triangle two sides of which are 18 cm and 10 cm and the perimeter is 42 cm

Answer 1

Answer:

$perimeter \: of \: triangle = sum \: \\of \: all \: sides \\let \: third \: side \: be \: x \\ 18 + 10 + x = 42 \\ 28 + x = 42 \\ x = 42 - 28 = 14cm$