Respuesta :

wegnerkolmp2741o

Answer:

b1 = 9 cm

Step-by-step explanation:

The formula for area of a trapezoid is

A = 1/2 (b1+b2) *h

We know Area = 135 CM ^2, Height = 10 CM, b2 = 18 cm

Substituting these in

135 = 1/2 (b1+18) *10

Multiply 1/2*10

135 = 5 (b1+18)

Divide both side by 5

135/5 = 5/5 (b1+18)

27 = b1+18

Subtract 18 from each side

27-18 = b1+18-18

9 = b1

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