The phrase "approximately as much" is correct and usable in written English.
It can be used when comparing quantities or amounts that are similar but not exactly the same.
Example: "The new model costs approximately as much as the previous version, making it a competitive option."
Alternatives: "roughly the same amount" or "about the same quantity".
It's decided there's approximately as much light as there should be.
NetZero Energy Homes (NZEHs) are designed to achieve zero energy balance annually (i.e., produce approximately as much energy as consume).
In particular, using an expendable launch vehicle involves the single use of a vehicle that costs approximately as much as a jet transport.
"All in all, Trump knows approximately as much about national security as he does about the nuclear triad - which is to say, almost nothing".
By now, he said, he has invested approximately as much in the account -- which he described as a "conservative, broad mixture in stocks, bonds and other investments" -- as he has put into real estate.
"...the fact that it must have cost approximately as much to produce as it does to array Mrs. Billy Rose suitable for an evening at the theatre, won't necessarily limit its engagement here".
The major congeners in Penta are IUPAC congeners 47 and 99, which account for approximately 75% of the total mass, with approximately twice as much BDE-99 (PeBDE) as BDE-47 (TBDE).
After approximately 5 wk, mice fed the unsupplemented diet weighted approximately 70% as much those fed the supplemented diet.
Phillips' new bulbs can now compete on energy usage as well: they produce about 200 lumens of light per watt, approximately twice as much as a typical office fluorescent.
Glucose has received particular attention because it is the preferred and primary source of energy for the brain, which requires a steady supply of around 100 mg/min of glucose in adulthood and approximately twice as much in childhood.
