In triangle PQR, PQ = 6 cm, PR = 8 cm, and QR = 12 cm. Calculate the area of the triangle PQR ?
A. 23.33 cm2
B. 17.5 cm2
C. 21.33 cm2
D. 28.67 cm2
Answer : C. 21.33 cm2
Explanation:
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- In triangle PQR, by using heron’s formula
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- S = P + Q + R / 2
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- S = 6 + 8 + 12 / 2
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- = 26 / 2 = 13
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- S = 13
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- Area of the triangle PQR = sqrt ( S (S – P) * (S – Q) * (S – R) )
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- = sqrt ( 13 (13 – 6) * (13 – 8) * (13 – 12) )
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- = sqrt ( 455 )
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- Area of the triangle PQR =
21.33 cm2
