find the area of quadrilateral ABCD in which a b is equal to 24 cm, angle b a d is equal to 900 cm and b, c and the form an equilateral triangle of side 26 CM
Answers
Step-by-step explanation:
The area of quadrilateral ABCD is 412.76 cm²
Step-by-step explanation:
Step 1 : Quadrilateral ABCD forms two triangles.
Equilateral triangle BCD with sides 26 cm and right angled triangle BAD with base 24 cm and hypotenuse 26 cm.
Step 2 : Using Pythagoras theorem get the height AB of the right angled triangle and the height of the Equilateral triangle.
AB = Square root of (BD² - AD²)
= Square root of (676 - 576)
= square root of 100 = 10 cm
Height of the Equilateral triangle :
Height = square root of (26² - (26/2)²)
= Square root of (507) = 22.52 cm
Step 3 : Calculate the area of the two triangles.
Area of a triangle = ½b × h
Area of the right angled triangle = ½ × 24 × 10 = 120 cm²
Area of the Equilateral triangle = ½ × 26 × 22.52 = 292.76 cm²
Step 4 : Sum the two areas to get the total area which is the area of quadrilateral ABCD.
292.76cm² + 120 cm² = 412.76 cm²
It is given that
ABCD is a quadrilateral in which ∠BCA = 900 and AB = 13 cm
ABCD is an equilateral triangle in which AC = CD = AD = 12 cm
In right angled △ABC
Using Pythagoras theorem,
AB2 = AC2 + BC2
Substituting the values
132 = 122 + BC2
By further calculation
BC2 = 132 – 122
BC2 = 169 – 144 = 25
So we get
BC = √25 = 5 cm
We know that
Area of quadrilateral ABCD = Area of △ABC + Area of △ACD
It can be written as
= ½ × base × height + √3/4 × side2
= ½ × AC × BC + √3/4 × 122
Substituting the values
= ½ × 12 × 5 + √3/4 × 12 × 12
So we get
= 6 × 5 + √3 × 3 × 12
= 30 + 36√3
Substituting the value of √3
= 30 + 36 × 1.732
= 30 + 62.28
= 92.28 cm2