The square of a number decreased by 15 is twice the number. find the number
1 answer:
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Answer:
Total area = 237.09 cm²
Step-by-step explanation:
Given question is incomplete; here is the complete question.
Field book of an agricultural land is given in the figure. It is divided into 4 plots. Plot I is a right triangle, plot II is an equilateral triangle, plot III is a rectangle and plot IV is a trapezium, Find the area of each plot and the total area of the field. ( use √3 =1.73)
From the figure attached,
Area of the right triangle I =
Area of ΔADC =
=
=
=
=
= 30 cm²
Area of equilateral triangle II =
Area of equilateral triangle II =
=
= 73.0925
≈ 73.09 cm²
Area of rectangle III = Length × width
= CF × CD
= 7 × 5
= 35 cm²
Area of trapezium EFGH =
Since, GH = GJ + JK + KH
17 =
12 =
144 = (81 - x²) + (225 - x²) + 2
144 - 306 = -2x² +
-81 = -x² +
(x² - 81)² = (81 - x²)(225 - x²)
x⁴ + 6561 - 162x² = 18225 - 306x² + x⁴
144x² - 11664 = 0
x² = 81
x = 9 cm
Now area of plot IV =
= 99 cm²
Total Area of the land = 30 + 73.09 + 35 + 99
= 237.09 cm²
