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The height of a triangle is 12 centimeters more than its base. The area of the triangle is 189 square centimeters Find the base and height of the tiangle?

The height of a triangle is 12 centimeters more than its base The area of the triangle is 189 square centimeters Find the base and height of the tiangle class=

Respuesta :

reinhard10158

Answer:

C

Step-by-step explanation:

the area of a triangle is

baseline × height / 2

so, we know in our case

b(b+12) = 189 cm²

b² + 12b - 189 = 0

let's try to solve this by completing the square.

that means we try to find the expression

(b + k)² + c

that is equal to

b² + 12b - 189

(b + k)² + c = b² + 2kb + k² + c = b² + 12b - 189

so,

2k = 12

k = 6

and then

k² + c = -189

6² + c = -189

36 + c = -189

c = -225

(b + 6)² - 225 = 0

(b + 6)² = 225

b + 6 = 15

b = 9

so, the baseline b = 9 cm.

the height b+12 = 9+12 = 21 cm.

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