Final answer:
Option e) 18.19 × 2.28 yields a product of 41.4732, which when rounded to the nearest tenth gives 41.5, and thus is an underestimate of the exact value.
Step-by-step explanation:
To determine which of the calculations, when rounded to the nearest tenth, provides an underestimate, we must evaluate each expression and then round the result.
- a) 39.45 × 1.7: When multiplied, the exact product is 67.065. Rounding to the nearest tenth would give us 67.1.
- b) 27.54 × 0.74: The exact product is 20.3796. Rounding to the nearest tenth would give us 20.4.
- c) 9.91 × 8.74: The exact product is 86.5784. Rounding to the nearest tenth would give us 86.6.
- d) 78.95 × 1.26: The exact product is 99.477. Rounding to the nearest tenth would give us 99.5.
- e) 18.19 × 2.28: The exact product is 41.4732. Rounding to the nearest tenth would give us 41.5.
An underestimate occurs when the rounded value is less than the exact value. In this case, choice e) 18.19 × 2.28 is the one that when rounded to the nearest tenth, 41.5, is less than the actual product 41.4732, thereby providing an underestimate.