How many different ways can 13 questions on true-false test be answered if a student answers every question?
1 answer:
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9514 1404 393
Answer:
252.8 cm²
Step-by-step explanation:
The missing side of the right triangle can be found from the Pythagorean theorem:
s² = 20² -16² = 400 -256 = 144
s = 12 . . . . cm
The area of a right triangle is more easily found using the traditional area formula:
A = 1/2bh
A = 1/2(12 cm)(16 cm) = 96 cm² (left-side triangle)
The area of the triangle on the right can be found from Heron's formula. The semiperimeter is ...
s = (16 +20 +23)/2 = 29.5
The area is ...
A = √(29.5(29.5 -16)(29.5 -20)(29.5 -23)) = √(29.5·13.5·9.5·6.5)
A = √24591.9375 ≈ 156.818 . . . . . cm² (right-side triangle)
Then the total area of the figure is ...
A = 96 cm² +156.818 cm² = 252.818 cm² . . . . total area
