Question

2. In AABC, ZB=90°.D is the mid-point of AB and
DE || BC. If AB = 9 cm and AC = 15 cm, find the
perimeter of DECB. ​

Answer 1

Answer:

This is your step by step answer

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Step-by-step explanation:

AB = 9cm

AC = 15cm

AC is the hypotenuse in the triangle.

AB is the perpendicular line.

BC is the base in the triangle.

By using Pythagoras theorem.

Hypotenuse = Base^2×Perpendicularline^2

= AC^2 = BC^2 × AB^2

= 15cm^2 = BC^2× 9cm^2

= BC^2 = 15cm^2 - 9cm^2

= BC^2 = 225cm - 81cm

=BC^2 = 144cm

= BC = sq. root of 144cm

= BC = 12cm

DE^2 = AE^2 - AD^2

= DE ^2= 7.5cm^2 - 4.5cm^2

=DE ^2= 56.25cm - 20.25cm

= DE^2 = 36cm

=DE= Sq. root of 36cm

=DE = 6cm

Area of a trapezium = 1/2 ×Height×(base1×base2) ×

1/2×4.5cm×(6+12)cm

= 1/2× 4.5cm×18cm

=1/2×45/10cm×18cm

=9×9/2cm

81/2cm

=40.5cm^2