Answers
Answer:
:By dividing the quadrilateral into two triangles and applying Heron’s formula, we can calculate the area of triangles.
Heron's formula for the area of a triangle is: Area = √s(s - a)(s - b)(s - c)
Where a, b, and c are the sides of the triangle, and s = Semi-perimeter = Half the Perimeter of the triangle
Now, ABCD is the park shown in the figure below
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A park, in the shape of a quadrilateral ABCD, has ∠C = 90°, AB = 9 m, BC = 12 m, CD = 5 m and AD = 8 m. How much area does it occupy?
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Solution:
By dividing the quadrilateral into two triangles and applying Heron’s formula, we can calculate the area of triangles.
Heron's formula for the area of a triangle is: Area = √s(s - a)(s - b)(s - c)
Where a, b, and c are the sides of the triangle, and s = Semi-perimeter = Half the Perimeter of the triangle
Now, ABCD is the park shown in the figure below
A park, in the shape of a quadrilateral ABCD, has ∠C = 90°, AB = 9 m, BC = 12 m, CD = 5 m and AD = 8 m. How much area does it occupy?
We have ∠C = 90°, AB = 9 m, BC = 12 m, CD = 5 m and AD = 8 m.
Let's connect B and D, such that BCD is a right-angled triangle.
In ∆BDC, apply Pythagoras theorem in order to find the length of BD
BD2 = BC2 + CD2 [Pythagoras theorem]
BD2 = 122 + 52
BD2 = 144 + 25
BD = √169
BD = 13 m
Area of quadrilateral ABCD = area of ∆BCD + area of ∆ABD
Now, Area of ∆BCD = 1/2 × base × height
= 1/2 × 12 m × 5 m
= 30 m²
Now, in ∆ABD, AB = a = 9 m, AD = b = 8 m, BD = c = 13 m
Semi Perimeter of ΔABD
s = (a + b + c)/2
= (9 + 8 + 13)/2
= 30/2
= 15 m
By using Heron’s formula,
Area of ΔABD = √s(s - a)(s - b)(s - c)
= √15(15 - 9)(15 - 8)(15 - 13)
= √15 × 6 × 7 × 2
= 6√35
= 35.5 m² (approx.)
Area of ΔABD = 35.5 m²
Therefore,
Area of park ABCD = 30 m² + 35.5 m² = 65.5 m²
Thus, the park ABCD occupies an area of 65.2 m².
°°° Explanation °°°
To find zero of the polynomial, p(x)=0
(i) If p(x)=x+5=0 then x=−5, i.e. −5 is the zero.
(ii) If p(x)=x−5=0 then x=5, i.e. 5 is the zero.
(iii) If p(x)=2x+5=0 then x= 2
−5 , i.e. 2−5 is the zero.
(iv) If p(x)=3x−2=0 then x= 32
, i.e. 32 is the zero.
(v) If p(x)=3x=0 then x=0, i.e. 0 is the zero.
(vi) If p(x)=ax=0 then x=0, i.e. 0 is the zero.
(vii) If p(x)=cx+d=0 then x= c−d
, i.e. c −d
is the zero.