Respuesta :

Answer:

78.9 grams

Step-by-step explanation:

We are asked to find mass of the rock rounded to the nearest tenth.

We know that rounding to nearest tenth means rounding to one digit after decimal.

We can see that hundredths value in our given number is 5, so we will round up to nearest tenth as:

Therefore, the mass of the rock rounded to the nearest tenth would be 78.9 grams.