Question

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Answer 1

Of two traingles

• 2×1/2BH
• BH
• 3(2)
• 6ft²

Of 3 rectangles

• 3LB
• 3(10)(3)
• 9(10)
• 90ft²

TSA

• 90+6=96ft²

Answer 2

96 ft²

Explanation:

As the base of the prism (the triangle) is an equilateral triangle (the sides are the same length), the surface area of the prism comprises:

• 3 congruent rectangles
• 2 congruent triangles

Area of a rectangle = width × length

⇒ area of the rectangle = 3 ft × 10 ft = 30 ft²

Area of a triangle = 1/2 × base × height

⇒ area of the triangle = 1/2 × 3 ft × 2 ft = 3 ft²

Total surface area = 3 × area of the rectangle + 2 × area of the triangle

= 3 × 30 ft² + 2 × 3 ft²

= 90 ft² + 6 ft²

= 96 ft²