Solving Word Problem Involving Surface Area of Rectangular Prism

Jason is wrapping a present. The box he is using is a rectangular prism with a length of 8 dm, a width of 5 dm and a height of 4 dm.

• He will solve the surface area.

• He will solve for the area of the six faces and find the sum of their area.

• He will solve the area of the three different faces and multiply each by 2, then find the sum. The answer will be expressed in square units.

• He will use this number sentence

  SA= 2(lw)+2(lh)+2(wh)

2. Mary wants to wrap her rectangular gift with a dimension of 15 cm by 6 cm by 2 cm. What is the least amount of wrapper can she use to wrap the gift?

• 264 cm

• 256 cm²

• 264 cm is the least amount of wrapper she can use to wrap the gift.

• 264 cm² is the least amount she can use to wrap the gift.

3. Joel is called to solve the surface area of the rectangular prism on the left. Joel answered the problem this way:

SA= 2lw + 2 lh + 2 wh

= 2 (11x5) + 2 (11x6) + 2 (5x6)

= 2 (55) + 2 (66) + 2 (30)

= 110 + 132 + 60

= 302

Is Joel's answer correct? Why?

• Yes, because he followed the correct formula.

• Yes, because adding all the area of the surfaces will give you 302.

• No, because the answer is not expressed in square units although 302 is correct

• No, because the answer is 300 square units

4. A wooden cabinet needs repainting. How much surface area needs to be painted if the box has a length of 8 cm, width of 5 cm and height of 6 cm?

• 236 cm

• 236 cm²

• 236 is the surface area that needs to be painted

• 264 cm² is the surface area that needs to be painted

5. Which of the following is the best answer for the problem below:

6. Gerald owns an antique shop. He is applying a coating to a rectangular jewelry box whose dimension is 5 cm by 3 cm by 4 cm. The can of varnish is enough to cover 80 cm². Is there enough varnish left in the can to coat the jewelry box? Explain your answer.

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