I need help plzzzz!!!!!! find the area
2 answers:
Answer:
area = 387 ft^2
3 bags
Step-by-step explanation:
See the picture below.
The pentagon is made up of 5 congruent triangles. One triangle is shown on the bottom right figure.
The left figure shows half of the triangle. We need to find h, the height of the triangle.
For a regular pentagon, the measure of each interior angle is
(n - 2)180/5 = 108
Half of the angle is 54 deg.
tan A = opp/adj
tan 54 = h/7.5
h = 7.5 * tan 54
h = 10.32 ft
Area of half triangle = bh/2 = 7.5 ft * 10.32 ft/2 = 38.7 ft^2
The pentagon is made up of 5 larger triangles or 10 half triangles.
Area of pentagon = 10 * 38.7 ft^2
Area of pentagon = 387 ft^2
1 bag is good for 150 ft^2.
387 ft^2/150 ft^2 = 2.6
She needs 2.6 bags, so she must buy 3 bags.
Answer: 3 bags
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