A circle is represented by the equation x2+y2=445. a) State the radius. b) Find y if point A(-9,y) is on this circle.
1 answer:
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Answer:
<h3>Option D) 294 sq cm is correct</h3><h3>∴ the surface area of the rectangular pyramid is 294 sq cm</h3>Step-by-step explanation:
First we have to split the net into 4 triangles and 1 rectangle
Given a = 12 cm ,b = 6 cm and d = 13 cm
<h3>To find the surface area of the rectangular pyramid:</h3>Now find the area of the rectangle base
= 72 sq. cm
<h3>∴ Rectangle base area=72 sq cm</h3>Now to find the area of the triangle on the left
= 39 sq cm
<h3>∴ Left triangle=39 sq cm</h3>Since all the triangles are congruent , you will need to multiply by 2 to get the combined area of the triangle on the left and on the right.
Area of left and right triangles= 2(39)
=78 sq cm
<h3>∴ Area of left and right triangles=78 sq cm</h3>Find the area of the triangle on the bottom
= 72 sq cm
<h3>∴ Bottom triangle area=72 sq cm</h3>Since the bottom of the triangle is congruent to the top triangle, multiply that by 2 to get a combined area of the triangle on the bottom and top
Area of top & bottom triangles=2 (72)
= 144 sq cm
<h3>∴ Area of top & bottom triangles= 144 sq cm</h3>Finally add the area of the 4 triangles to the area of the rectangular base we get
=72 + 78 + 144
= 294 sq cm
<h3>∴ the surface area of the rectangular pyramid is 294 sq cm</h3><h3>∴ option D) 294 sq cm is correct.</h3>