A triangular field has two side equal as 75 m, and third one as 90 m. What is the cost of ploughing the area at the rate of ₨. 15.6/m²?
Answer & explanation
Correct answer: option 1
s = \(\frac{a + b+ c}{2}\)
= \(\frac{75 +75 + 90}{2}\) = 120
Area = \(\sqrt {s(s - a)(s - b)(s - c)}\)
= \(\sqrt {120(120 - 75)(120 - 75)(120 - 90)}\)
= \(\sqrt {120 \times 45 \times 45 \times 30}\)
= 60 x 45 = 2700
Cost = 2700 x 15.6 = ₨. 42120