Answer:
DE = 6 cm
Step-by-step explanation:
Let DE = x cm.
Since DE is parallel to AB therefore by the alternate interior angles theorem, m∠BAD = m∠ADE and m∠ABE = m∠DEB ............(1)
As AD is an angle bisector of ∠A, therefore m∠EAD = m∠DAB ; Since BE is an angle bisector of ∠B ⇒ m∠ABE = m∠EBD.
Therefore, from (1) We get , m∠EAD = m∠ADE and m∠EBD = m∠BED.
So, the triangles ADE and EDB are then isosceles with AE = ED and ED = DB.
So AE = DE = DB = x, and since the perimeter of ABDE is 30 cm, then
12 + x + x + x = 30
⇒ 12 + 3x = 30
⇒ x = 6
Hence, the length of DE is 6 cm.
Answer:
A. 162 m²
Step-by-step explanation:
==>Given:
Isosceles trapezoid with:
base a = 19m
base b = 35m
Perimeter = 74meters
==>Required:
Area of trapezoid
==>Solution:
Recall: the length of the legs of an isosceles trapezoid are equal.
Perimeter of isosceles trapezoid = sum of the parallel sides + 2(length of a leg of the trapezoid)
Let l = leg of trapezoid.
Perimeter = 74m
Sum of parallel sides = a+b = 19+35 = 54m
Thus,
74 = 54 + 2(l)
74 - 54 = 2(l)
20 = 2(l)
l = 20/2 = 10m
Let's find area:
Area = ½(a+b)*h
a = 19
b = 35
h = ?
Using Pythagorean theorem, let's find h as follows:
h² = l² - [(35-19)/2)²
h² = 10² - [16/2]²
h² = 100 - 64
h² = 36
h = √36 = 6m
Area = ½ x (a+b) × h
= ½ × (19+35) × 6
= ½ × 54 × 6
= 27 × 6
Area = 162m²
I answer . The white ones are better trust me, but u have to keep them keep clean!
I would multiply both sides by negative one and then take the smaller of the two variables and subtract that from both sides, simplify and solve.
