Question

Let ABCD be an isosceles trapezoid (AB//CD). Draw AE, BF perpendicular to CD (E, F belong to CD), Let AB = 8cm, CD = 18cm, AD = 13cm.
a) Prove that triangle ADE = triangle BCF
b) Calculate DE, CF.
c) Calculate AE.

Thanks for solving the homework

Answer 1

A trapezoid is a plane figure bounded by four sides. Therefore, the required answers are given below;

a) ΔADE = ΔBCF (Side-Angle-Side congruent property)

b) DE = 5 cm and CF = 5 cm

c) AE = 12 cm

Plane figures are shapes that are formed by straight boundaries referred to as sides. Examples include; square, rectangle, trapezium, etc.

A trapezoid is a family of quadrilaterals., these are figures that have four straight sides.

In the given question, the required answers are:

a) To prove that ΔADE = ΔBCF

Thus,

AE ⊥ DC  (given)

BC ⊥ DC  (given)

<AED = <BFC = $90^{o}$

AE = BF (height of the trapozoid)

<ADE ≅ <BCF (congruent property of two triangles)

Therefore, it can be concluded that;

ΔADE = ΔBCF (Side-Angle-Side congruent property)

b) Given that AB = 8 cm, and DC = 18 cm.

Then,

CD = DE + EF + FC

18 = DE + 8 + FC   (since EF = AB)

18 - 8 = 2 DE     (since DE = FC)

DE = 5 cm

Thus, DE = 5 cm and CF = 5 cm

c) To determine the value of AE, we have to apply the Pythagoras theorem. So that;

$/Hyp/^{2}$ = $/Adj 1/^{2}$ + $/Adj 2/^{2}$

$13^{2}$ = $AE^{2}$ + $5^{2}$

169 - 25 =  $AE^{2}$

$AE^{2}$ = 144

AE = $\sqrt{144}$

     = 12

AE = 12 cm

For more clarifications on the measure of the sides of a trapezoid, visit: https://brainly.com/question/28007759

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